Heat oven to 350°F. Grease and flour two 9-inch round baking pans.

Stir together sugar, flour, cocoa, baking powder, baking soda and salt in large bowl. Add eggs, milk, oil, and vanilla; beat on medium speed of mixer 2 mins. Stir in boiling water (batter will be thin). Pour batter into prepared pans.

Bake 30 to 35 mins or until wooden pick inserted in center comes out clean. Cool 10 mins. Remove from pans to wire racks. Cool completely.

For one-pan cake, grease and flour 13x9 inch baking pan. Heat oven to 350°F. Pour batter into prepared pan. Bake 35 to 40 mins. Cool completely.