3 oz unsweetened chocolate, chopped
1/2 c butter, sliced
1 c boiling water
2 c sugar
2 eggs, separated
1 t vanilla
1/2 sour cream
1 t baking soda
2 c less 2 T unbleached all-purpose flour
1 t baking powder
Place the chocolate and butter in a bowl with the boiling water and whisk till melted. Whisk in the egg yolks, sugar and vanilla.
In a large cup, mix the baking soda and sour cream. Add this mixture to the chocolate mixture and whisk by hand.
Add the baking powder and flour to the chocolate mixture and blend well.
With a mixer, beat the egg whites till they are stiff but not dry. Add 1/3 of the egg whites to the chocolate mixture and blend thoroughly. Fold in remaining egg whites. Don't overmix.
This makes 5 cups of batter. See the Wilton cake batter chart to determine how much batter you need and time/temperature to cook for the pan you will be using: http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm.
If you have 2" round pans, bake at 350 degrees for 45-60 minutes.
I use this recipe for most stacked chocolate cakes that I make. It is very moist for a dense cake. The baked cakes freeze well, making decoration day a lot quicker.