Line 2 9 in. cake pans with waxed or parchment paper, and lightly grease and flour them for easy cake removal.

Melt 3 squares unsweetened chocolate in microwave or double boiler and set aside.

Sift together and set aside:

2 1/4 cups sifted flour
2 tsp. baking soda
1/2 tsp. salt

In mixer, beat 4 oz. sugar with 2 1/4 cups packed brown sugar.

Add, and beat in 3 large eggs.

Add melted chocolate and 1 1/2 tsp. vanilla.

Stir in dry ingredients alternately with 8 oz. sour cream, beginning and ending with flour to incorporate fat.

Stir in 1 cup boiling water.

Pour into prepared cake pans and bake at 350 for 25 minutes or until cake pulls away from sides of pan and tests clean in center.