Fat Daddio’s heating cores have smooth sides, a flat rim, and even wall thickness, which ensure professioinal results. Each core is manufactured with premium 3003 aluminum and anodized to facilitate easy cleanup, durability and baking efficiency. Place the core in the centre of the pan. fill the pan around the core with cake batter and then fill the core to the same level as the cake. Bake as usual. allow to cool for about 15 in the pan / core and then carefully remove the core pan. remove the cake from the core pan and insert into the hole left in the cake. allow to cool further and then carefully invert onto a cake cooling rack to firm up. Although the core is 4″ deep, it can be used in the 3″ pans – just fill to suit.