Pizza is an oven-baked flat bread typically topped with a tomato sauce, cheese and various toppings. The modern pizza was invented in Naples, Italy, and the dish has since become popular in many parts of the world. An establishment that makes and sells pizzas is called a "pizzeria". Many varieties of pizza exist worldwide, along with several dish variants based upon pizza. Pizza is cooked in various types of ovens, and a diverse variety of ingredients and toppings are utilized. In 2009, upon Italy's request, Neapolitan pizza was safeguarded in the European Union as a Traditional Speciality Guaranteed dish.
In restaurants, pizza can be baked in an oven with stone bricks above the heat source, an electric deck oven, a conveyor belt oven or, in the case of more expensive restaurants, a wood- or coal-fired brick oven. On deck ovens, pizza can be slid into the oven on a long paddle, called a peel, and baked directly on the hot bricks or baked on a screen. When made at home, it can be baked on a pizza stone in a regular oven to reproduce the effect of a brick oven. Another option is grilled pizza, in which the crust is baked directly on a barbecue
grill. Greek pizza, like Chicago-style pizza, is baked in a pan rather than directly on the bricks of the pizza oven.
Pizza is available frozen, as round traditional pizzas or in portion-size pieces. Methods have been developed to overcome challenges such as preventing the sauce from combining with the dough and producing a crust that can be frozen and reheated without becoming rigid. Modified corn starch is commonly used as a moisture barrier between the sauce and crust. Traditionally the dough is partially baked and other ingredients are also sometimes precooked. There are frozen pizzas with raw ingredients and self-rising crusts.
A form of uncooked pizza is available from take and bake pizzerias. This pizza is created fresh using raw ingredients, then sold to customers to bake in their own ovens
or microwave ovens
Another approach is using a fresh dough, sold with sauce and basic ingredients, to complete before baking in oven.