Well, it's a dough flattened into a circle and covered with a base sauce. Usually a tomato sauce. Then, you can add whatever combination of toppings you'd like. Popular choices are pepperoni, mushrooms, ham, sausage, and black olives. Then it's all baked in an oven until the crust browns up and the cheese melts. It's typically cut into 8 pie slice pieces to serve. This particular one appears to include ingredients popular in Mexican foods.