You can trim the dome off cake layers with a long serrated knife as shown in “Piece of Cake,” but for those of us whose aim isn’t so precise, there’s the cake leveler. Resembling a coat hanger, it’s essentially a wire stretched between its two sides. To use it, adjust the leveler’s height to agree with the amount you need to remove. Draw the cake leveler through the cake, using a gentle back-and-forth slicing motion, and then remove the top. Levelers also come in handy if you want to split one cake layer into two (or more) even layers. A basic cake leveler, like the one shown at left, costs around $6.