Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round baking pans.
In a large bowl, stir together the sugar, flour, cocoa, baking powder, baking soda, and salt.
Add the eggs, milk, oil, and vanilla, and mix for 2 minutes on medium speed of mixer. Stir in the boiling water last. Batter will be thin.
Pour evenly into the prepared pans.
Bake 30 to 35 minutes in the preheated oven, until the cake tests done with a toothpick. Cool in the pans for 10 minutes, then remove to a wire rack to cool completely.