Heat oven to 350 degrees F. Grease & flour 2 9-inch round baking pans or one 13 x 9 x 2-inch baking pan.
In large mixing bowl, stir together sugar, flour, cocoa, baking powder, baking soda & salt.
Add eggs, milk, oil & vanilla; beat on medium speed of electric mixer for 2 minutes.
Remove from mixer; stir in boiling water (batter will be thin). Pour batter into prepared pans.
Bake for 30-35 minutes for round pans, 35-40 minutes for rectangular pan or until wooden pick inserted in center comes out clean.
Cool 10 minutes & remove from pans. (if desired)
Cool completely. (Cake may be left in rectangular pan)