A brand of rectangular, pre-baked toaster pastries made by the Kellogg Company. Pop-Tarts have a sugary filling sealed inside two layers of rectangular, thin pastry crust. Some varieties are frosted. Although sold pre-cooked, they are designed to be warmed inside a toaster. They are usually sold in pairs inside foil packages, and do not require refrigeration. Popular flavors include chocolate, apple, frosted blueberry, frosted strawberry, frosted brown sugar cinnamon, cherry, raspberry and s'mores.