“Cooked” is Gen Z slang, basically means “done.”

• “This guy’s cooked.” (He’s had too much/he’s out of it/he’s screwed)

• “I’m cooked, chat.” (I’m out of options/it’s over for me)

In the context of this meme, which is from the movie Back to the Future, Marty is in the past and using slang that hasn’t entered popular use yet, so Doc thinks he’s talking about cooking food and is confused about what he means.

Also not to be confused with similar “Let them cook” (they’re onto something, let’s see where this goes).