Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9 inch round pans.
In a large bowl, combine sugar, flour, cocoa, baking powder, baking soda and salt. Make a well in the center and add eggs, milk, oil and vanilla. Beat for 2 minutes at medium speed. Stir in boiling water.
Pour into two 9 inch pans. Bake at 350 degrees F (175 degrees C) for 30 to 35 minutes, or until a toothpick inserted into the cake comes out clean. Cool for 10 minutes in the pan, then turn out onto a wire rack and continue cooling.