Instructions

1. Cake directions: Prepare three 8″ round pans with cake release and parchment circles on the bottom. I also put cake release on the parchment circles. Preheat oven to 300 degrees.Sift together and set aside: the cake flour, soda, salt, and unsweetened cocoa powder.
   Bring to room temperature: eggs-separated into two bowls, sour cream, and butter.
   Cream the softened butter with the sugar on low speed of mixer. You don’t want to incorporate any air into this batter. Use low speed throughout entire process. Once butter/sugar mixture is well mixed, add egg yolks one at a time incorporating each completely before adding the next one. Next, add the vanilla and the cappuccino mix/coffee mixture pouring slowly in a stream until well blended. At this point you may have to stop the mixer and scrape the bowl. Alternate the sour cream with the flour/salt/soda/cocoa mixture scraping the bowl often until the mixture is well blended.
   Whisk the egg whites until they are nicely separated and frothy, but not beat up stiff. Fold this into the first batter. Pour the batter into the three cake pans and bake for 60 minutes or until a tooth pick comes out clean. When done, allow to cool for about 5 to 10 minutes and then pop out of pans onto waxed paper to cool. I have good luck popping them out right after they come out of the oven too.

Authentic German Butter Cream Filling and Top Frosting instructions
In a 2 quart sauce pan, mix the cornstarch and sugar. Stir in the milk and bring to a boil, stirring constantly, on medium heat. Boil for approx. 2 1/2 minutes. Remove from heat and stir 1/4 cup of the hot mixture into the beaten egg yolks, stirring while doing so. Add this egg yolk mixture back into original mixture and return to medium heat, boiling for two more minutes stirring constantly. After the two minutes, turn off the heat, add the 2 tblsp. butter and the vanilla and stir unto the butter is melted then set aside to come to room temp. Place a piece of plastic wrap over the mixture to keep a skin from forming. Remove the remaining butter from the refrigerator and cut up into pieces and place into the mixer bowl and allow to come to room temp. When the bottom of the pan containing the pudding mixture is completely at room temp., and the butter in the mixer bowl is the same, whip the butter until it is creamed well, and add a tablespoon at a time of the pudding mixture. Keep the mixer on high speed until all of the pudding is mixed in and the frosting/filling mixture is a good spreading consistency. Place this mixture in the refrigerator for now, covered with plastic wrap.

Cappuccino Frosting for side of the cake instructions:
Cream the butter until nice and fluffy, add one cup of the powdered sugar at a time, alternating with the cappuccino/coffee mixture, the salt, and the cocoa until all of the ingredients have been incorporated. Scrape the bowl and add the vanilla, and beat on high speed for about 10 to 15 minutes. (make sure you stop the mixer when adding the powdered sugar and start slowly while mixing or you will have powdered sugar everywhere!)

Putting the cake together:
Using the German butter cream, cover the bottom layer with about 1/4 of the mixture. Place the next layer on and do the same thing. Place the top layer on, but don’t frost yet. Cover the sides of the cake with the cappuccino frosting and frost smooth. Reserve enough of your frosting to fill a piping bag so that you can make a bottom border and hopefully, a few decorations on top. (Depends on how heavy your hand is on a border.) Now smooth a layer of your German butter cream on the top of the cake. Fill another piping bag with the remaining butter cream and pipe whatever decorations you wish on the top of your cake. If you have enough of your cappuccino frosting, you can over-pipe onto your German butter cream. Keep refrigerated and covered.