Did Col. Landa actually recognize Shosanna?

I believe it depends on the viewer whether to take it as an indication to the accident or not. When we as viewers of the movie see the whole conversation happening in every moment we feel the fear of revelation of Shosanna's original identity to the Colonel, given we are already been introduced with his cunning and cold but cruel behavior. We feel such because the whole story is shown from the start how she survives from the unnecessary chasing of the Colonel (from her point of view). So when after a long time Shosanna meets with him, we as well as her, feel fear to see the executioner of her family and if he might recognize her! So maybe the Colonel did not identify her (chances is 99%). But we (Shoshana and us) automatically feel fear. His ordering milk for her or the last sentences by him:

I did have something else to ask you. But right now, for the life of me, I can't remember what it is. Oh well, must not have been important.

pushes us in the wrong direction out of this fear. As long as the conversation went on, we hold our breath with her and when he leaves, we loose it! So I think the conversation was nothing regarding him identifying her. He was just trying to dig into her individuality as a quality security officer (Though bad in nature, we can't ignore his responsibility to his work!). But the fear of blowing her cover makes us make out unnecessary meaning and that is how a winning script is!

I think it would be more consistent if he didn't. As said,

1. It would be dangerous to let her go.

2. He couldn't know what she and the basterds would do (even they didn't know at that time), so he couldn't plan ahead on that.

3. He didn't see her face in the farm. I think that having pictures (as some suggested) is unrealistic (I believe they were not very common at that time, specially in rural areas).

But mainly:

I think Tarantino wanted to show how good Shosanna was at hiding her emotions.

• The fact that he asked milk can interpreted being due to his own taste for milk plus false-consensus. But the reason for this element in the scene imply that this detail would help to destabilize Shosanna.
• In the four 'interrogations' (Lapadite, Shosanna, Bridget and Aldo+'little man') by him, he apparently uses the same trick of pause + stare to inspect the level of tension built on the target. In the strudel scene, the camera goes to Shosanna to show how calm she stayed on that situation (differently from Lapadite), so Landa believed she was not hiding anything. The 'question' was abandoned because he never intended to ask anything really. In all other scenes, it was made clear that the targets of the interrogation displayed a behavior Landa interpreted they were hiding something.
• I think the cigarettes are there to add to Landa's search for nonverbal clues of stress, fear or anxiety. When he says he wants to ask another question and stares at her and he camere focus on her face: She both 1) doesn't stop looking in the eyes and 2) does not smoke. Lapadite, when Landa says there will be more questions, immediatly crosses his arms, and when Landa first mentioned the Dreyfus, he asks to smoke his pipe, and finally he can't look landa in the eyes. There are more details on the script which are not shown on the movie(like entire paragraphs, like when Landa persuades Lapadite that his duty at war time was to protect his daughters, and if he cooperate they'd be stopped being harassed by the german army). It is on youtube. It says, specifically, that when Lapadite finally broke down, he was with his pipe in his mouth. Maybe the strudel has to do with anxiety testing as well.

But on that scene she did show signs of anxiety at some moments, like heavy breathing.

Anyway, I don't really care about what Tarantino has to say about it unless it's based on what was shown at the movie (on some missed detail, for example). I prefer to interpret it the way it sounds more consistent with what was shown on screen. But I believe these are pretty strong points showing what tarantino wanted for this scene.

I seem to be in the minority here, but I actually think Col. Landa did not recognize Shosanna. He did not get a good look at her in the beginning of the film. And if he suspected she would try to get revenge, he would have to think it would be primarily directed at him. Why allow somebody to potentially interfere with his plans to defect? He wouldn't know she planned to burn down the theater only after he left. I think the various pieces of evidence in the restaurant (cream, milk, forgotten question) are just for suspense.

With that said, I'd love to hear a definitive answer from Tarantino.

Another answer of "presumably not" is given in the IMDb FAQ:

Did Col. Landa know that Shosanna was the girl he let escape when he meets her at the cafe?

Presumably not. He never saw her face while she was running away from him, so there is no way he could have known that she was the girl, although we don't know how detailed were the files Landa had on the Dreyfus family. It is possible he had a very good description of her or even a photo. Being a very skilled detective and interrogator, he acts as polite and respectful as possible and never shows all his cards until he is certain about the outcome. The beginning of the film showed Landa having a friendly conversation with Monsieur LaPadite whom he suspected of hiding the Dreyfus family, but asked for certain details about them to see how Mr. LaPadite responded, pretending to not really be sure about the details of the Dreyfus family was hint enough for Landa to know he was lying and confirm that LaPadite was hiding the Dreyfuses. Keep in mind that Landa also knew who Aldo, Donny and Omar were simply by interrogating the swastika marked soldiers. So he could very easily have known or suspected that Madame Mimieux was in fact Shosanna Dreyfus, simply by height, hair colour, eye colour and descriptions he had gathered from interrogations of other Dairy Farmers in the area. Perhaps the reason he ordered the milk and the cream was that he suspected she was Jewish, but as she kept her calm and even tried the strudel, cream and all, he either dismissed his theory or chose to ignore it. It's also possible, going with the assumption that Landa did indeed know who she was, that Landa was just testing her nerves. The more he prolonged the stress of him sitting there with her, the more uncomfortable she'd likely become. Not to mention she probably didn't have much of an appetite with him sitting there. While she kept her calm, it was also obvious she was still nervous. Perhaps when he said he had something else to ask her...then he paused...gave her an intense stare was just to gauge her reaction. As a cat toys with a mouse. Either for his own amusement or to see if she would try running at which point he could apprehend her.

I always wondered about this and after reading the above remarks I would agree it is highly probable that he did indeed know it was her.

I'd just like to add that the close-up on him extinguishing his cigarette into the strudel at the end of the conversation, immediately after extolling its deliciousness, to me signifies the two-faced nature of his character, whereby he puts on an act to achieve his objectives in a given encounter, especially in an interrogation. Tarantino discusses this point in this video:

We are left wondering if he actually appreciated the strudel or if he was merely using it as a device to create tension.

I'm almost positive he knows it's her.

Those little things he says are just like his personality to poke at her. Inquiring deeper than most people about her aunt and uncle and how they died. Ordering milk for her knowing she had been taken in and saw her family murdered at a dairy farm, watching her as he said it.

Jews in hiding weren't hiding because no one would notice them, they probably made the mistake of leaving behind pictures, the state probably had photo ideas. And Landa doesn't seem like the type to forget a face.

And that last thing he couldn't remember that must have just not been important. He ended the movie betraying Hitler. That's not a split-second decision. He had probably known at that time the state of things in the war and was planning his betrayal at that time.

Why exert himself more than needed?

They weren't just hiding in a dairy farm, the Dreyfus family were dairy farmers, this adds significance to the cream.

Second, Landa's eyes when he looks at her and says there is something else take on a chilling intensity, exactly like when he got serious with the father in the opening scene.

I think he was considering in real time whether to expose her, weighed up his plans as mentioned above and decided against it.

Yes, Landa knew who Shosanna was at that time. The key hint is in the question he claims to have forgotten to ask.

Landa is the Jew Hunter. He is portrayed as someone who finds everyone he sets his mind to finding, as someone who is very good at his job, at sniffing out every lie and enjoying it. He proves he has already done investigations into Shosanna by asking about her projectionist, so the only real question is how much else he already knows.

The key hint that he knows Shosanna is in the question he admits to have "forgotten" to ask, and which "must not have been important", the first of which is a straight lie, and the second of which is technically the truth, in a cruel way. It's not important because he knows the answer already.

In truth, he knows exactly what question he would have asked, if it had been a normal interrogation of an unknown person. In the Nazi ideology, and for the Jew Hunter in particular, nothing is more important than heritage in determining who is a Jew or not. He diligently inquires about her aunt and uncle when she mentions them, what their names are, what they are doing now. And with all that prompting, he conveniently forgets to ask the most natural question of all:

Who are your parents?

This is so far out of character for Landa that the only reasonable conclusion is that he did not forget the question, that he deliberately did not ask it because he already knows the answer, and thus, who Shosanna is.

He doesn't ask the question because he doesn't want to spook Shoshanna more than he already does. He does not want to press her for a (no doubt prepared) lie about her parents, like he will press von Hammersmark before the film's climax, or even be forced to arrest her on the spot in order to not compromise himself. He simply doesn't want to push her anywhere near a lie.

And yet he can't help but enjoy the little game he's playing with Shosanna (and for our, the viewers', benefit), by dropping hints that he knows: ordering milk for her, by being exceptionally jovial in what is a life-or-death situation for Shosanna, by meaningfully extinguishing the cigarette butt in the cream.

That also means he's already been planning to betray his country for his own advantage at that point, and is only looking for a real opportunity. He recognizes the cinema as that opportunity for acquiring the ultimate bargaining chip with the Allied command. That requires letting Shosanna off the hook and giving the go-ahead for the movie night.

This heavily depends on interpretation of the scene. While it could easily be true that Landa indeed knew "Emmanuelle's" true identity, it could also just as easily be true that he was unsure and was just toying with her emotions to see if she would break, similar to the farmer who silently gave away his position after Landa stared at him intensely.

Hard to say, but considering from the audience's knowledge, he never got a detailed look at her when he massacred her family. Whether he had a better description of her is questionable, otherwise I doubt he would keep her alive for that long. I think he knew Shosanna only by reputation, and not by physical means. However, it is certain that he was indeed suspicious of her in the restaurant - but he could have been testing her to confirm, otherwise if he knew it was her for sure, he wouldn't need to play games - regardless of the fact that that's part of his wicked personality.

The milk, cream and strudel - all point out to the fact that he is considering she may very well be Shosanna, but also to see how she would react. Would she keep her cool, or would she give her position away? The fact that she held up her facade amazingly well could've tuned in to Landa that she wasn't easy prey, and perhaps not Shosanna... YET.

I would say that Col. Landa actually did know. One thing you have to actually believe is that Col. Landa really forgot what he was trying to say... when talking to Shosanna. Think about it... what does that mean, plus, why did he simply put his cigarette out and leave in what appeared to be a hurry. It seems that Landa is already letting events unfold. He knows its her. Nazis probably did have picture identifications of her. If not, there are so many other ways. For example, it really isn't hard to recognize that Shosanna actually hasn't been living with her "aunt and uncle." Most likely, because she was the last Jew in that area, and she's the only one unaccounted for, she could be the only possibility.

Another assumption you could make is that he changes his mind about what he wants to do when he says there was something he actually wanted to talk about with her. His facial expression already posed to deal her death sentence and all of a sudden he lets her live again. It might have been planned out, but it could be coincidence that he let her live twice just to have one Jew roaming around to give him meaning to his job.

Of course he knew who she was and would be insulted that you presumed otherwise. Throughout the movie he is 10 steps ahead of everyone. Also, he likes to mess with people and make them squirm. In this case, he wants to make sure everything goes according to (his) plan.

Oh yes. He knew. And anyone who thinks otherwise is just wrong. He is a detective first and foremost, as Tarantino stated... He knew, and what's more, he must have regarded her with a certain respect in being able to hide in plain sight like she was, after escaping from the death squad.

He would've known that it must not be easy to keep her cool whilst sitting with the very man who ordered your entire family to be killed.

Then, as if to test her resolve one final time, he says the crack about wanting to ask her about something else, but not being able to remember... after a cold, brutal stare... right into her soul it seemed... Ouch!

He 100% knows. Like he said to Aldo Raine, sometimes things aren't too good to be true. The universe can be very giving one time out of a million.

1. He is an excellent detective and would most certainly have family photos. He does not chase her down or fire at her in the opening scene because he is saving her for later. He is actually the most brilliant person in the film.
2. He orders her milk and a food containing pig fat. He is, in his mind, further denying her religious freedom.
3. Exposing her would comprises the change of venue.
4. The smaller venue means less collateral damage. Too much collateral damage would limit the options of the allied forces (all eggs in a smaller basket). He has this information leaked to the actress who he knows is a spy. He is the "all-knowing" until the last scene.
5. He insists she be there to run the projecter. She would be collateral damage.
6. His comment about having something to say that he forgot was meant to invoke fear. While he is brilliant, it certainly would take him time to read her responses and determine the best course of action. Her fear of discovery would lead to two responses: fight or flight. She didn't run, so he knows she is going to seek revenge. Her cinema has lots of films that he knows mean very little to her and are very flammable. He was doubling down.

Colonel Landa said "au revoir" in French, meaning "I'll see you again", or "until we meet again".

I think he did know very well that it was her. But he was a strange man. I think he respected her a bit for escaping the Germans twice, with the way he thought so highly of Germans and so lowly of Jews. He thought perhaps that she was different. He alludes to her life hiding on a dairy farm, "for the mademoiselle... a glass of milk"; "ah, ah, ah wait for the cream."

And the question at the end, he likes to watch the anxiety and perhaps he respects her even more for showing so little. But I think at that time, he wasn't so concerned anymore about his work with the army, the government was making strides to see that the Germans preserve their nation pride. He knew it was going bad for Germany and he was on the wrong team. So he wasn't going to go out of his way to prove Emanuelle was actually Shosanna.

I'm convinced he knew of her true identity. I believe the reason he decided to let her be was because he had probably reported to his superior commanders that he had executed the entire Dreyfuss family. No way he would have reported that he allowed one to escape.

Now, it's several years later and the country's Hero (the private) is smitten with her, and for Landa to reveal her true identity as a Jew would cause great embarrassment and humiliation for the Reich and bring a court-martial against him for falsifying his original report.

So, he had no intention of blatantly calling her out but due to his sadistic nature, he did enjoy watching her squirm by his questions and actions (such as ordering cream, when Jewish people never consume dairy products with a meal).

I believe he did not recognise her, mainly because it would be tantamount to ascribing superpowers to him to say that he recognised a girl whose face he never really saw after at least a decade, even though he is portrayed as the ultimate ‘Jew hunter’.

Just one point about the glass of milk that perhaps has not been made yet: Despite being a perfect gentleman in many ways, he knows the importance of imposing his authority in certain key situations . Ordering the strudel and then the glass of milk for her is a power move intended to convey to her that despite his outward hospitality, Shosanna is not an ordinary guest there, that he’s in charge and she will do what he says. As a French civilian woman at a table of German officers during the occupation of her country, she must not be allowed to forget her place even while receiving hospitality. Hence it’s coffee for him and milk for her, and she would have to be okay with it.

On the ‘forgotten question’, galmeida above said it best:

The 'question' was abandoned because he never intended to ask anything really. In all other scenes, it was made clear that the targets of the interrogation displayed a behavior Landa interpreted they were hiding something.

That said, there are some great arguments on the other side, which just goes to show how brilliantly the movie is written.