Seven Sins Chocolate Cake

Seven Sins Chocolate Cake

Not long ago I sampled a cake from a bakery that boasted seven forms of chocolate. "Seven Deadly Sins" they called it.  It had two types of dark chocolate frosting, milk and white chocolate pastry cream, white chocolate curls... you get the idea. All those chocolates sound interesting when used in one cake, but I thought those "seven sins" could be more... sinful.  The gears began to turn.

Since then I've been scribbling in my recipe journal and testing decadent flavor combinations; a bit of espresso here, a bit of whiskey there...

Last week I finally pieced together what I consider the best of the best, and here you have it. A truly sinful Seven Sins Chocolate Cake. 

Shall we meet the players?

1,2,3:  The trio of pastry creams all work together without being overly sweet, and they all retain their individual nuances of flavor when eaten together.  I could eat a vat of each on any given day.

4: Can we all agree that a "Seven Sins" cake should have Devil's Food as a base? Yes? Good. This one is moist and has a structure sturdy enough for torting.

5: Milk chocolate marshmallow frosting - it's as good as it sounds, and probably a bit lighter tasting than you'd expect.

6: Dark chocolate drizzle is the perfect counter for the light-tasting marshmallow frosting.  It demands attention, both in flavor and appearance.

7: Squares of chocolates and chocolate shavings are a pretty and tasty decoration. It's like dessert on top of dessert.

Seven Sins Chocolate Cake

Yield: 15+ servings                                                                                         [click for printable version]
I recommend making this cake over the course of 2 days. The devils' food cake and pastry creams can be made on the first day, and the frosting, drizzle and assembly can be completed on day 2.

Devil's food cake:
This is my favorite devils' food cake recipe adapted from a Rose Levy Beranbaum recipe. This double layer cake gets torted and filled with three types of pastry cream.

Tip: Instead of picking up a torted cake piece with your hands, slide it onto a large plate. This will keep the cake from breaking into pieces and makes it easy to slide the piece back onto the filled cake.

1 oz. fine quality unsweetened baker's chocolate, chopped evenly
3/4 cup plus 1 1/2 tbsp. unsweetened cocoa powder
1 cup hot coffee  (can use hot water or decaf coffee if caffeine sensitive)
2 eggs
2 egg yolks
1/4 cup sour cream
1 tbsp vanilla bean paste or vanilla extract
2 1/4 cups all purpose flour
1 1/2 cups light brown sugar, tightly packed
1 tsp baking soda
1/2 tsp salt
16 tbsp (2 US sticks) unsalted butter, softened

1. Preheat oven to 350 degrees.  Grease two 9-inch cake pans with vegetable shortening and line with a circle of parchment paper. Grease paper and flour; tap out excess and set pan aside.
2. In a medium bowl, whisk the chocolate, cocoa and hot coffee (or water) until smooth. Set aside.
3. In another bowl, whisk the eggs, yolks, sour cream, half the chocolate mixture and vanilla until just combined.
4. In the bowl of a stand mixer fitted with the paddle attachment, mix the flour, brown sugar, baking soda and salt on low for 30 seconds. Add the softened butter and the remaining chocolate mixture.  Mix on low speed until the dry ingredients are moistened. Raise the speed to medium and beat for 30 seconds. Scrape down the sides of the bowl.
5. With the mixer off between additions, add the egg mixture in two parts, starting on medium-low speed and gradually increasing to medium. Beat on medium speed for 45 seconds after each addition to incorporate the ingredients and strengthen the structure. The batter will be fluffy. Scrape down the sides of the bowl.  Using a silicone spatula, scrape the batter into the prepared pans and smooth the surface evenly with a small offset spatula.
6. Bake for 30-40 minutes (check at 30). Cake is does when a toothpick tester comes out clean and the cake springs back when pressed in the middle.  Let the baked cakes cool in the pan on a wire rack for 10 minutes, then turn cake out onto a wire rack sprayed with cooking oil.  Let cool completely.

Trio of pastry creams:

Tip:  Be sure to temper eggs carefully! If you goof a little and pastry cream turns out lumpy, pass it through a fine sieve before refrigerating.

2.5 oz. dark chocolate
2.5 oz. white chocolate
2.5 oz. milk chocolate
¼ cup cornstarch
2 cups evaporated milk
2 eggs
4 egg yolks
¾ cup granulated sugar
3 tablespoons unsalted butter
2 tbsp. whiskey
3 tbsp. dulce de leche (find this canned in the ethnic food aisle)
1-2 tsp. espresso powder (to taste)

1. Have ready three small bowls (2 cup size), wiped spotless of any moisture.  Chop the chocolate evenly and place each type of chocolate in a separate bowl.  Set aside.
2. In a small bowl, dissolve the cornstarch in 1/2 cup of the milk. Beat the whole eggs, then the yolks, one at a time, into the cornstarch mixture.
3. In a saucepan, combine the remaining milk and the sugar; bring to a boil, whisking constantly.
4. While whisking the egg mixture, slowly pour 1/3 of the boiling milk into it, to temper the eggs.
5. Return the remaining milk in the saucepan to medium-low heat.
6. Pour the hot egg mixture into the saucepan in a thin stream, whisking, so as to not scramble the eggs.
7. Whisk constantly until the mixture thickens and begins to boil.  Remove from the heat and pour the hot pastry cream over the chopped chocolate, dividing evenly between the three bowls.  Let stand for 2 minutes, and then stir each bowl until mixture is well incorporated.  Mix 1 tbsp. butter in each of the bowls.  When butter has melted and is thoroughly combined, fold in 2 tbsp. whisky into the dark chocolate pastry cream; 3 tbsp. dulce de leche into the white chocolate pastry cream;  1-2 tsp. espresso powder into the milk chocolate pastry cream.
8. Press a sheet of plastic wrap directly on the surfaces of each type of pastry cream so they do not form a skin. Cool to room temperature.
9. Refrigerate until ready to use.

Milk chocolate marshmallow frosting:
12 tbsp (1 1/2 US sticks) unsalted butter, softened
2 2/3 cups powdered sugar
6 oz. milk chocolate melted and slightly cooled
7 oz. marshmallow cream

1. With a hand mixer or standing mixer fitted with the whip attachment, beat butter for 3 minutes until fluffy.  Add powdered sugar and mix on low until incorporated.  Add melted chocolate and beat until fluffy. Add marshmallow cream and beat until frosting has lightened in color and all ingredients are well combined.
2. Scrape down bowl and mix again.  Transfer 3/4 cup to a piping bag or zip-top bag with the corner snipped for later use. 

Fill and frost the cakes:
Cut each cake in half horizontally (this is called "torting"); pipe a line of frosting around the edge of the first cake piece. This makes a reservoir in which to hold the pastry cream (this is extra insurance, sometimes pastry cream is lax if not well refrigerated). Spread the pastry cream inside the icing ring and top with another cake piece.  Pipe an icing line as before and fill white chocolate dulce de leche cream; repeat with the next cake piece and milk chocolate mocha cream.  Top with the final cake layer and frost the entire cake.  You may choose to crumb coat the cake and refrigerate, then do a final smooth coat of icing (recommended).

Dark chocolate drizzle:

Note: This portion should not be made ahead. The chocolate thickens quickly and needs to be applied to the cake 10-15 minutes after making it.

4 oz. dark chocolate chopped evenly
1/2 cup whipping cream
1/4 cup light corn syrup
2 tsp. vanilla

1. Place chopped chocolate in a medium bowl. In a 4-cup measure, heat cream until very hot but not boiling (about 45 seconds for me, but all microwaves vary); you can also do this in a saucepan over medium heat if you don't have a microwave. 
2. Pour hot cream over chocolate and let stand for 2 minutes.  Whisk until all chocolate is completely melted and mixture is consistent.  Whisk in corn syrup and vanilla.  Let mixture stand until slightly thickened - about 10-15 minutes.  Pour over cake; allow the mixture to run down the sides of the cake in fingers. 

Final flourishes:

Chocolate shavings

Your choice of chocolate pieces - this version has 16 squares of chocolate and 16 silver chocolate buttons (product sources are listed in blog post)
Remaining 3/4 cup frosting in piping bag/zip-top bag

1. Pipe frosting in mounds around the outer edge on top of the cake.  Sprinkle-on chocolate shavings.  If using, place a chocolate square in the center of each mound and place a silver button in front of each square of chocolate.

Important! Keep this cake refrigerated, but be sure to bring it to room temperature before serving.  Pastry creams and frosting flavors are fully developed at room temperature.