Chocolate Cobblestone Loaf

1/2 cup boiling water
1 3/4 cups flour
1 teaspoon baking powder
1/2 cup shortening
2 egg yolks
3/4 cup sour milk
1/2 cup cocoa
1 teaspoon baking soda
1/2 teaspoon salt
1 1/2 cups granulated sugar
1 teaspoon vanilla extract
2 egg whites

Sift together dry ingredients. Cream sugar and shortening. Add egg yolks, sour milk and water and mix well. Add dry ingredients.

Beat egg whites until stiff and add to mixture. Blend, but don't beat. Pour into a greased loaf pan and bake at 375 degrees F for 25 to 30 minutes. It is done when a wooden pick comes out dry.