Pop-Tarts is 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 or microwave oven. They are usually sold in pairs inside foil packages, and do not require refrigeration.