For the Cake:
Preheat oven to 350°F. Grease two 9-inch round baking pans; dust with cocoa.
Stir together sugar, baking mix, cocoa, salt, baking powder and baking soda in large bowl. Add eggs, milk, oil and vanilla; beat on medium speed of mixer 2 minutes. Stir in boiling water (batter will be thin). Pour into prepared pans.
Bake 35 to 40 minutes or until wooden pick inserted in center comes out clean. Cool 5 minutes; remove from pans to wire racks. Cool completely. Frost with "PERFECTLY CHOCOLATE" CHOCOLATE FROSTING.
For the Frosting:
Melt butter, stir in cocoa.
Alternately add powdered sugar and milk, beating to spreading consistency. Add small amount of additional milk, if needed (to desired consistency).
Stir in vanilla.