Reader Evan asks: if we use lidded Pullman pans to create perfectly rectangular loaves of bread, why don’t we use lidded cake layer pans to make cake layers that don’t dome? That is an ingenious question, Evan! You may have a big future as a product designer. However in this case my guess is that you’d find a lid did you more harm than good. Why? Because the centers of rising cake layers are much more delicate than the tops of rising bread loaves. If you’ve ever tapped the top of a cake layer before it’s completely done you’ve probably noticed that the indentations you make with your fingers don’t spring back even after the layer is returned to the oven. Tap on it too hard and the whole center can fall in. This is because cakes aren’t “all structure” like loaves of bread. Sure they contain flour and water (and eggs) that help them stay up, but that structure is a delicate balance. It carries a heavy load of sugar and fat, and will fall without much provocation. Contact with a lid, I’m pretty sure, would be enough to cause a cake later’s structure to collapse.