Most cakes are usually cut into eight or 12 slices because these numbers provide for a perfect, even cut. Cutting a cake into 10 slices is not common, but it has been done before and will certainly be done again.
Choose and Prepare the Knife
Long, thin blades are the best knife choice to use when cutting a cake into any amount of slices. Start by running the knife under very hot water. In addition to sanitizing the knife, running it under hot water will ensure the knife will slice easily through the cake. It is recommended to use a knife that is at least 10 inches to 12 inches long so the cake can be sliced in half in one cut. Add hot water to a paper towel or cloth towel to wipe the cake residue off the knife after cutting each slice.
Cut the Cake In Half
The first cut that should be made into the cake to successfully cut a cake into 10 pieces should be a slice directly down the middle of the cake. After the knife is prepped and dried, slice one line, either horizontally or vertically down the cake. Make sure this line is even and keep a steady hand. From here, the cake is going to be sliced into two sets of five even pieces, working with one half at a time.
Consider the Cake a Clock
This is where the cake cutting gets tricky. Look at the cake as it if is a clock. Make tiny, distinguishable markings along the edge of the cake to distinguish the cake to have set spots, just like a clock. Make these various markings around the cake in 12 spots total, six on each side of the cake that has now been cut in half. When cutting this cake, viewing it as if it is a clock will be the best way to explain where the pieces will be cut.
Cutting the Cake
Using the knife, trace a slice that would extend from three quarters of the way between the two and three to halfway between the three and four. Cut this slice and repeat on the other half of the cake. These two pieces that have been cut out can be put to the side or served. Now take each of those four sections left (two on each side of the cake) and cut them each in half evenly. These are now ready to serve and the cake has been cut into 10 even pieces.