Per chef Mary Berry’s website, baking a cake on your oven’s top rack is a mistake because "the crust is formed too soon, the cake continues to rise, therefore the crust cracks."

Baked goods require even heating on all sides. The closer food is to an oven’s bottom or top, the closer it is to the heating elements that may overheat and crisp up certain areas.

To avoid overcooking parts of your baked goods, Berry suggests using the middle rack. However, sometimes moving your food from one rack to another can make the end result better.