What is a good kids food theme?

Go pizza. That's what we did for my son's three year old birthday. Each kid was given a chunk of their own dough and got to make their own. You can talk about the colors and make it really healthy: green and yellow peppers, brown mushrooms, red tomatoes, black olives, yellow pineapple, etc. The kids colored their own aprons (practicing letters to write their names on it). For dessert, we had dessert pizza: sugar cookie with cream cheese frosting (dyed red), shredded white chocolate for cheese, and fruit that we put in a pizza box. You could also have a "pizza parlor" play center where they can use a cash register and take pretend orders/play oven/kitchen.