Chocolate angelfood cake

I made a chocolate angel food cake for my ungrateful brother's birthday. It was delicious!

Chocolate Angel Food Cake
1 2/3 Cup egg whites (1 dozen)

1 cup minus 1 tbsp cake flour

3/4 cup granulated sugar

1 cup granulated sugar

1/4 cup cocoa

1/2 tsp. salt

1-1/2 tsp. cream of tartar

1-1/2 tsp. vanilla

Sift flour, cocoa & 3/4 c. sugar 4 times. In a large bowl of electricmixer, combine egg whites, salt, cream of tartar & vanilla. Beat on highspeed until whites are stiff and stand in peaks. At medium speed add 1 c.sugar until blended. At low speed, add the flour mixture. Push batter intoa 10 inch tube pan. Bake at 375 for 35 minutes. Invert at once and lethang until completely cold. Frost with chocolate butter frosting.

Chocolate buttercream frosting

6 tbsp butter, softened

1/4-1/2 c milk

1/2 c cocoa powder

approx. 1/2 bag powdered sugar

1 tsp vanilla

Cream butter and vanilla in mixer. Mix in cocoa powder. Alternate mixing in milk and powdered sugar until you reach spreading consistency.