Basic White Cake

In a small bowl of electric mixer, let egg whites warm to room temperature - about 1 hour. Meanwhile, preheat oven to 350 degrees. Grease and flour two 9-inch layer cake pans. Sift flour with baking powder and salt, set aside. At high speed, beat whites until foamy. Gradually beat in 1/2 cup sugar, beating well after each addition. Beat until soft peaks form when beater is slowly raised, set aside. In large bowl of electric mixer, at high speed, cream butter with rest of sugar and the extracts until light and fluffy. At low speed, beat in flour mixture (in fourths), alternately with milk (in thirds), beginning and ending with flour mixture. Beat in egg whites just until batter is smooth--about 1 minute. Pour batter into prepared pans, bake 25 to 30 minutes, or until surface springs back when gently pressed with fingertip. Cool in pans 10 minutes. Remove from pans, cool thoroughly on wire racks. Fill and frost as desired.