They could probably offer in Y the soup that they give in F. It's usually very good, and would be the easiest thing to make.

I remember reading about a test done some years back, on a BA flight I think. They outfitted a complete kitchen on a plane, brought in fresh food and a top chef. Even then, the hot food had nowhere near the flavor and taste of a restaurant, due I think to the pressurization and humidity, and how the aromas don't have the same effect in your sinuses or something like that. The point was that fresh cold food will always taste better than hot food in an airplane environment.