1 cup buttermilk
1 teaspoon baking soda
1 cup (2 sticks) margarine
2 cups granulated sugar
3 egg yolks
2 squares unsweetened chocolate, melted
3 cups cake flour
1/2 teaspoon salt
1 teaspoon vanilla extract
3 egg whites, stiffly beaten

Mix buttermilk and baking soda together; let stand to expand. Cream margarine and sugar. Add yolks and chocolate; mix. Add buttermilk mixture, then sifted ingredients. Add vanilla extract and beat well. Fold in egg whites. Bake in greased, lined tube pan at 300 degrees F for 1 hour.

This cake is delicious unfrosted or, for a special touch, frost with Icing for Brownstone Front Cake.

Icing for Brownstone Front Cake
1 cup (2 sticks) butter or margarine
2 cups granulated sugar
1 (5 1/3 ounce) can evaporated milk
1 1/2 teaspoons vanilla extract

In saucepan, combine margarine, sugar and milk. Dissolve over low heat. Bring to boiling point and simmer 45 minutes uncovered. Remove from heat; add vanilla extract. Cool to room temperature, then beat well. Spread on cake.