*Greek yogurt or buttermilk can be substituted. If you don't have buttermilk, you can substitute by stirring 2 teaspoons of white vinegar or lemon juice into 2/3 cup of regular milk. Allow the mixture to stand for 5 minutes, or until thickened and slightly curdled.
**This cake can also be baked in two 8-inch or 9-inch diameter cake pans. The cake layers may bake up slightly thinner, and the bake times may need to be adjusted.
If you just want to make chocolate cake, here is my favorite recipe: Chocolate Cake from Scratch.