Randi - from Millbury, OH
For any large cakes (more than 10 inches) we recommend using a heating core in the center of the pan. For a full sheet cake (18 x 26), you should use 2 heating cores for best results. To use, grease or spray your baking pan and the inside and outside of the heating core. Place some batter inside the core, stand in the pan and fill the pan with the remainder of the batter.