1 1/4 c. egg whites
1 1/2 c. sugar
1/4 c. cocoa
3/4 c. sifted cake flour
1/2 tsp. cream of tartar
1/4 tsp. salt
1 1/2 tsp. vanilla

Add salt to egg whites. Beat until foamy. Add cream of tartar and beat stiff (form stiff peaks). Fold in sugar gradually. Fold in vanilla. Sift flour and cocoa together 3 times. Fold in carefully.

Pour into ungreased tube pan. Bake on low rack at 325 degrees for 1 1/4 hours. Cool by inverting pan. Frost with Chocolate Butter Icing.