3/4 c. sifted cake flour
1/3 c. sifted cocoa powder
1 tsp. instant coffee powder (optional)
1 1/2 c. sugar
12 egg whites, room temperature
1 tsp. cream of tartar
1/4 tsp. salt
1 tsp. vanilla

Combine flour, cocoa, coffee powder (if using), and 3/4 cup of the sugar. Beat egg whites with cream of tartar and salt until whites hold soft peaks. Gradually beat in remaining 3/4 cup sugar and continue beating until whites hold stiff peaks. Beat in vanilla. Gently fold in flour mixture, being careful not to overmix. Pour batter into an ungreased 10 inch tube pan. Run knife through batter to release any air bubbles. Bake at 325 degrees until toothpick stuck into center comes out clean, about 45 minutes. Cool cake completely. Run knife around edge of pan to release cake.