 In its simplest form, a reflector oven is simply a box or collar that partially surrounds the food, with an open side that faces the heat source, which is generally either a hearth fire or a portable stove, depending on the situation in which the food is being prepared.In Colonial America this method of baking meat, fowl, quick bread, or pastries, was a very popular method for hearth cooking.A reflector oven that uses the Sun as its primary heat source is known as a solar cooker.