Chocolate Angel Food Cake
["3/4 c. cake flour", "4 Tbsp. Baker's breakfast cocoa", "1 1/4 c. egg whites (10 to 12 egg whites)", "1/4 tsp. salt", "1 tsp. cream of tartar", "1 1/4 c. sifted granulated sugar", "1 tsp. vanilla"]
["Sift flour once, measure, add cocoa and sift flour again. Beat egg whites and salt on large platter with flat wire whisk. (We use electric mixer.)", "When foamy, add cream of tartar and continue beating until eggs are stiff enough to hold up in peaks, but not dry.", "Fold in sugar carefully, 2 tablespoons at a time, until all is used.", "Fold in vanilla.", "Then sift small amount of flour over mixture and fold in carefully; continue until all is used.", "Pour batter into ungreased angel food cake pan and bake in a slow oven at least one hour.", "Begin at 275\u00b0, increasing heat slightly to 325\u00b0 after 30 minutes."]
["cake flour", "cocoa", "egg whites", "salt", "cream of tartar", "sugar", "vanilla"]