Mahogany Pound Cake
["1 c. butter, softened", "2 c. sugar", "1 c. firmly packed brown sugar", "6 eggs, separated", "2 1/2 c. all-purpose flour", "1/2 c. cocoa", "1 c. sour cream", "1/4 tsp. baking soda", "1 tsp. vanilla extract"]
["Cream butter.", "Gradually add sugars, beating well at medium speed.", "Add egg yolks, one at a time, beating after each.", "Sift flour and cocoa together.", "Combine sour cream and baking soda. Add flour mixture to creamed mixture alternately with sour cream. Stir in vanilla.", "Beat egg whites; fold into batter."]
["butter", "sugar", "brown sugar", "eggs", "flour", "cocoa", "sour cream", "baking soda", "vanilla extract"]