Chocolate Peanut Butter Mousse Bombe

A few months ago, I bought a book called One Cake, One Hundred Desserts. Its premise is simple: learn one cake recipe, and then modify it 100 different ways to create 100 new desserts. Of course, I felt the need to tackle the one that had the most amount of chocolate possible. This recipe was originally for a "Double Chocolate Mousse Bombe" - using milk chocolate & dark chocolate mousse - but being the peanut butter lover that I am, I adjusted it a little.

(Before we begin, a fun fact: "Bombe" typically refers to any type of bowl-shaped dessert. It will not cause an explosion in your kitchen. Unless you don't let the mousse set properly (which happened in my second attempt) and then it's just messy - like an explosion and a landslide mixed together. But still yummy!)

Step 1: The Cake

You can use any chocolate cake recipe for this, but here's the one I used from the book:

• 3/4 cup all-purpose flour
• 1/3 cup cocoa powder, whisked to remove lumps
• 1 teaspoon baking powder
• 1/4 cup milk
• 2 tablespoons unsalted butter, cut into 2 pieces
• 1 1/2 teaspoons vanilla extract
• 3 large eggs, room temp
• 3 large egg yolks, room temp
• 3/4 cup sugar

This cake has a lot of steps, but is very yummy and not nearly as complicated as it appears:

• Preheat oven to 350.
• Grease bottom of 11" x 17" inch jelly roll pan (or cookie sheet with sides), line with parchment paper or aluminum foil, and grease & flour the paper/foil
• Combine flour, cocoa, and baking powder in large bowl. Set aside.
• Heat the milk and butter in a small saucepan over low heat. As soon as the butter is melted, remove from the heat and add the vanilla. Set aside.
• Using the whisk attachment of a stand mixer (or if using a hand mixer, the regular beaters), whip the eggs, egg yolks, and sugar in a large mixing bowl on high speed for 3 minutes. The mixture will triple in volume and turn a very pale yellow. Reduce the speed to medium and continue whipping for 3 minutes (if using a hand mixer, keep it on high speed). The mixture should continue to increase in volume and thicken.
• With the mixture on the lowest speed, slowly sprinkle 1/4 of the flour mixture over the eggs and mix until no trace of white remains. Repeat with the remaining flour mixture in 2 additions; reserve the empty flour bowl. When the flour is fully incorporated, the batter will be thick and stiff; if you let it pour off the whisk into the bowl, it will fall back on itself like a ribbon.
• Pour half of the batter into the empty flour bowl. Pour the warm milk mixture into the batter and stir gently to combine.
• Slowly pour the milk/batter mixture back into the mixing bowl, and using a rubber spatula, fold the mixtures together quickly but gently until fully blended. You will see tiny air bubbles appear on the surface; work quickly to prevent too much air from escaping.
• Gently pour into prepared pan, gently spreading it into all corners of the pan with a rubber spatula.
• Bake for 15-20 minutes, until the surface springs back when poked with your finger and a toothpick inserted comes out of the cake clean. Set the cake on a rack to cool.

Now comes the fun part: Assembling the Bombe!

• Line a 1 1/2 quart bowl (a 1/5 liter Pyrex works well) with plastic wrap, leaving plenty of overhang on the sides. (When the cake is finished, you will use the plastic wrap to remove the cake from the bowl).
• When the cake is cool, run a knife around the edge of the pan and turn the cake out onto a large cutting board. Remove the parchment paper or foil. Trim 1/4 inch from each side of the cake (the edges tend to be dry). Cut the cake into pieces like this:

This might be difficult to see, but basically, you want a square large enough to cover the top of your bowl. You want 6 equal sized squares, and 4 triangles (when 2 are put together, they equal the size of one of the smaller squares). The easiest way to measure is to lay your bowl upside down over one corner and cut a square. Then extend those lines all the way across & up the cake so you have two large squares and two rectangles. Set one aside to be your big square. Cut the other three pieces into smaller, equal pieces until it looks like the cake above.

To line the bowl: place 1 small square on the bottom of the bowl. Place 4 small squares on top of it, reaching above the top of the bowl (see picture below):

Next, insert your triangle pieces to fill in the gaps. They should fit snugly. Then, cut the excess off the tops so all pieces are even with the bowl.

Exciting news: any cake you have left over is free to be eaten at this point! (Except your big square... don't eat that yet!)

Now, on to make the mousse. You might be like me, and want to make the most of your time in the kitchen. With this recipe, it might seem that the best way to do that is to make the mousse while your cake is cooking and cooling, but you need to resist the urge. Instead, wash dishes, read a magazine, dance around the house in your apron as your husband looks at you like you've lost your mind... whatever it takes. The reason is this: you want to be able to put the mousse in the bombe before it begins to set.

So, once your bowl is ready, get to work on your first layer of mousse. The first one you put in will be on the top. I chose peanut butter mousse this.  Pour into bombe until the bowl is about half full (NOTE: this recipe does not use all of the mousse mixture. Put the rest in the fridge to set for 1-48 hours, and enjoy it on its own at your leisure!)  Tap the bowl gently to distribute the mousse evenly, and then place in the freezer as you prepare the dark chocolate mousse.

Pour dark chocolate mousse over peanut butter mousse in the chocolate bombe (by now, the PB mousse should be firm enough that the dark chocolate mousse - which is still very liquidy - does not run through.) This does not use all of the dark chocolate mousse, so be prepared to have leftovers!

To finish assembly:

• Place the large square of cake directly on top of the dark chocolate mousse and press gently. Trim edges to make it a circle.
• Pull the plastic wrap over the top to cover.
• Refrigerate until set (at least 2 hours, up to 48 hours)

The final step is the glaze. You don't want to apply the glaze until about 30 minutes before you serve the cake. Make sure your cake is FIRM FIRM FIRM (the second time I made this, I didn't let it set enough and it all slide apart).

CHOCOLATE GLAZE:

• 4 tablespoons unsalted butter, cut into 4 pieces
• 2 ounces semisweet chocolate, chopped
• 2 ounces unsweetened chocolate, chopped
• 1/4 cup corn syrup

Chocolate piles make me happy!

Bring a small pot of water to a gentle simmer. Combine all ingredients in a heatproof bowl that can sit atop the pot without touching the water. Place the bowl over the pot and stir until the ingredients are just melted and combined.

(This glaze hardens as it dries, and is also a good glaze for dipping fruit, or for topping ice cream. Store any leftovers in the fridge, and then melt in double boiler or in the microwave as needed).

Set the glaze aside the cool slightly while you turn out the bombe. Peel back the plastic wrap from the cake and turn the cake out onto a rack set over a baking sheet; you may have to pull slightly on the plastic wrap to get the bowl off. Gently remove the plastic wrap and discard.

Pour most of the glaze over the center of the bombe, letting it run down the sides. Using an offset spatula, spread the glaze in an even layer over the bombe, using the reserved glaze to fill any holes. Try to let the glaze do most of the work (good luck with that...) - the less you use the spatula, the less streaky the glaze will be. While the glaze is still wet, decorate the bombe with chocolate shavings, if desired. Let stand at room temp to set, about 30 minutes.

Use a large spatula to transfer the bombe to a serving plate. Serve immediately with whipped cream and fresh raspberries (if you're into that sort of thing).

NOTE: The glaze will be very shiny once it hardens. Once refrigerated, it loses some of its luster. It will develop a matte-like finish in the fridge, and will regain some of its luster once it returns to room temperature. However, it will never get quite as shiny as it was at first, so plan accordingly. Oh yes, and - it's delicious!

Overwhelmed yet? This is a lot of steps, but completely worth it when it turns out well. Enjoy!