Let's say that, from now until the time that you die, you could only have access to one very specific food. (For instance, if you say "pizza", what kind of toping(s) would always be on it.) What would it be? You can take nutrition into consideration, but it's ultimately just asking what food you like so much that you think you might be able to stand it, and only it, forevermore.
For me, I think a burrito could do it. It'd have sour cream, refried beans, beef, tomato, rice, lettuce/guacamole, shredded cheese, olives, onions, tuna and chili peppers. Yeah, that should do it. It's a food pyramid in every bite, just about.