Hi Michele! That happens because the edges of the pan bake the sides of the cake quickly and the middle takes longer and continues to rise. Glass pans cause this to happen more dramatically than light-colored metal pans do so if you can use metal pans you'll have flatter cakes. You can also wrap the pans with cake strips to insulate them, though commercial cake strips might not reach all the way around a pan that size. You can make your own cake strips by fully wrapping damp paper towel strips in tin foil and then wrapping that around the edge of the pan. 

• Reply