For the Cake: Arrange the oven racks in the upper and lower thirds of the oven and preheat the oven to 425°F.
3 cups All-Purpose Flour
3/4 cup Unsweetened Cocoa
1 teaspoon Baking Soda
1 teaspoon Salt
1 1/2 sticks Butter (at room temperature)
1 1/2 cups Granulated Sugar
2 large Eggs (at room temperature)
1 1/2 cups Milk
Whisk together the flours, cocoa, baking soda and salt in a medium bowl. Cream the butter and sugar in the bowl of an electric mixer at high speed until fluffy, about 4 minutes. Add the egg and milk and beat at medium speed until incorporated. At low speed, add the flour mixture in 2 batches, alternating with the milk, mixing until just blended. Put the batter into piping bags.
Line 2 baking sheets with parchment paper. Trace the base of an 8-inch cake pan (or any 8 inch circle) 4 times on the parchment paper, a template for the cake batter.
Flip the papers over, place them on sheet trays, and begin piping in the edge of circle, spiraling your way in to the center to form a perfect circle. Fill all four circles. Smooth the cake batter with a spatula. Bake for 7 to 8 minutes, until springy to the touch. Let cool on the sheets for 5 minutes, then transfer to a rack to cool completely.
2 stick Butter (softened)
1 teaspoon Salt
4 cups Powdered Sugar
1 teaspoon Vanilla Extract
2 cups Cream Cheese (softened)
1 cup melted White Chocolate
For the White Chocolate Filling: Meanwhile make each filling separately. Beat the butter, salt and powdered sugar at low speed until blended and then beat at high speed until fluffy, about 5 minutes. Add the vanilla and cream cheese and mix at low speed until blended, about 1 minute. Slowly mix in cooled melted chocolate. Place the filling into piping bag.
1 stick Butter (softened)
1/2 teaspoon Salt
2 cups Powdered Sugar
1/2 teaspoon Vanilla Extract
1 cup Cream Cheese (softened)
1/2 cup melted Dark Chocolate
For the Dark Chocolate Filling: Beat the butter, salt and powdered sugar at low speed until blended and then beat at high speed until fluffy, about 5 minutes. Add the vanilla and cream cheese and mix at low speed until blended, about 1 minute. Slowly mix in cooled melted chocolate. Place the filling into piping bag.
Working with one circle, pipe an even layer of white chocolate filling onto the base layer. Smooth the filling with a spatula or an offset. Place a piece of cake on top and pipe an even layer of the dark chocolate filling.
1/2 cup Chocolate Chips
1 1/2 cup Dark Chocolate (melted)
Place another layer of cake on top and pipe an even layer of the white chocolate filling. Sprinkle with the chocolate chips. Top with a final layer of cake. Pour the melted chocolate over the top and smooth with a spatula. Serve.