Preparation / Directions:
Sift flour, measure and resift with baking soda. Cream butter until very light and fluffy, add sugar and egg yolks and cream thoroughly. Melt chocolate over hot water and add to mixture. Add flour with mixture alternately, a little at a time, starting with flour. Beat well after each addition. Fold in egg whites beaten stiff but not dry. Bake in 2 8-inch square cake pans in a 350 F oven for 20-25 minutes or until the center is firm to the touch. Turn out onto a cake cooling rack and frost with Chocolate Butter Cream Frosting.