This extravagant cake is rich, rich, rich, and a chocolate lover’s delight. Make it for a gala party, where it will be a real showstopper. Here’s the game plan.
I created this recipe years ago when chocolate mousse cake became all the rage, similar to the molten chocolate lava cakes that seemed to pop up on menus everywhere.
Because the chocolate mousse cakes I had eaten were just OK — they were tender, but they and the mousse lacked oomph — I began experimenting. I found that cake flour is essential for a light, fine-textured cake. This is a low gluten bleached flour made with soft winter wheat, and it’s in supermarkets in boxes labeled Softasilk or Swans Down. I also found that egg yolks, in addition to whole eggs, gave the cake a fine, delicate crumb.
Instead of baking layers separately, what works best is to bake a nice tall chocolate cake in a 9-inch spring form pan and then divide it into three moist layers. You’ll have some leftover cake, which you’ll turn into crumbs for later.
Once the cake’s done, make the chocolate mousse. You spread cups of this luxuriously smooth concoction over all the layers and around the sides of the cake. And for even more chocolate, you spread the top of the cake with chocolate ganache, some of which runs down the sides of the cake.
But you’re not done yet. After the cake’s been refrigerated overnight you’ll take the crumbs made from the cake trimmings and press them onto the sides of the cake. And that’s it!
Your work is done. Just refrigerate the cake until serving time, and you’re good to go. I think it’s best to cut portions while the cake is cold. Let them stand for 10 to 15 minutes, and then present them.
Chocolate Mousse Cake
Makes 16 servings
I’ve given approximate percentages of cocoa in the bittersweet chocolate. Feel free to go down or up. Any percentage from 48% to 72% will work. Be sure to use heavy cream for the mousse (about 36% butterfat). Whipping cream’s butterfat is too low (30% to 32%), and the mousse will be too thin to hold a firm shape.
1 ½ cups cake flour (spoon flour into cups to overflowing, and level with a straight edge)
4 ounces bittersweet chocolate (62% cocoa butter), coarsely chopped
5 tablespoons water
8 tablespoons unsalted butter (1 stick), at room temperature
¼ teaspoon salt
1 cup granulated sugar
1 ½ teaspoons pure vanilla extract
2 large egg yolks
2 large eggs
¾ cup buttermilk
¾ teaspoons baking soda
2 large egg whites
12 ounces bittersweet chocolate (62% cocoa butter), chopped
8 tablespoons (1 stick) unsalted butter, cut into tablespoon-size pieces
1 tablespoon instant espresso
You have free articles remaining.
6 tablespoons hot water, in a small cup
3 cups heavy cream
½ cup confectioners’ sugar
1 ½ teaspoons pure vanilla extract
½ cup heavy cream
1 tablespoon light corn syrup
4 ounces bittersweet chocolate (62% cocoa butter), finely chopped
1. For the cake. Adjust an oven rack to the lower third position and preheat the oven to 350 degrees. Butter a 9-inch spring form pan, line the bottom with a round of waxed paper or cooking parchment, dust the bottom only with all-purpose flour, and knock out the excess.
2. Sift or pass the flour through a strainer to aerate and set aside. Put the chocolate into a small microwave-safe bowl and microwave on full power 1 minute. Add the water to the chocolate but do not stir, and microwave on full power 30 seconds. Now stir with a narrow flexible spatula until the chocolate is completely smooth; set aside.
2. Beat the butter and salt in a stand mixer with the paddle attachment (if you have one or with the beaters provided) until smooth and creamy looking, about 1 minute. While beating on medium speed, gradually add the sugar in a fine stream, taking about a minute. Scrape the bowl and beater, add the vanilla, and beat 4 minutes on medium high speed. Scrape the bowl and beater again. Add the egg yolks and beat just until incorporated on medium speed, about 30 seconds. Add the eggs one at a time beating well after each. Scrape in the chocolate (which may be tepid) and beat on low speed until thoroughly combined.
3. In a medium bowl, stir together the buttermilk and soda. In about a minute the mixture will become very bubbly.
4. On low speed, add the flour in 3 additions alternately with the buttermilk in 2 additions, beginning and ending with the flour, and mixing only until smooth. If you prefer, just do this by hand with a flexible spatula or wooden spoon.
5. In a medium bowl, whip the egg whites with a whisk or hand-held electric mixer until the whites form glossy peaks that droop at their tips. Don’t overbeat. The whites must be moist and fluffy. Fold the whites into the chocolate and scrape the batter into the prepared pan. Spread level.
6. Bake about 50 minutes, until the top of the cake springs back when gently pressed and a wooden skewer inserted into the center comes out clean. Cool the cake in its pan on a wire rack for 20 minutes. Unhinge the side of the spring form pan and lift it away. Cover the cake with a wire rack and invert the two. Remove the bottom of the spring form pan , cover the cake with another wire rack, and invert again so that the cake cools completely right side up on a wire rack. The cake will be about 2 ½ inches tall from base to center.
7. Wash and dry the sides of the spring form pan, clamp it shut, and center it onto a dessert platter.
8. When the cake is completely cool, turn the cake upside down so its bottom is on top. With a large serrated knife—and as evenly as you can—gently slice the cake into three ½-inch-thick layers—no thicker! Use toothpicks and a ruler to guide you. There will be leftover cake, which you will turn into crumbs. Just do this with your fingertips, and store the crumbs in a zip-top bag.
9. Set the top cake layer (the first layer you cut from the bottom of the cake) cut side up into the spring form pan and lay a sheet of plastic wrap on it. Wrap the remaining two layers in plastic wrap to prevent them from drying.
10. Now on to the chocolate mousse. Put the chocolate into the top of a double boiler on medium heat. If you don’t have a double boiler, put the chocolate into a medium-size metal bowl. Add an inch or so of water into a large skillet, and bring the water to the simmer over medium heat. Set the bowl of chocolate into the water and stir occasionally with a flexible spatula until the chocolate is melted and smooth. Make sure that not a drop of water actually gets into the chocolate or it will seize up.
11. Add the butter and stir with a flexible spatula until the butter has melted and is combined thoroughly with the chocolate. Remove from the double boiler or skillet and scrape the chocolate into a medium bowl. Dissolve the espresso in the hot water and pour over the chocolate. Stir the coffee into the chocolate and cool to room temperature, stirring occasionally. Before use, the chocolate must be at room temperature, no warmer. Test on the inside of your wrist.
12. In a chilled bowl with a chilled whip attachment, whip the cream with the confectioners’ sugar and vanilla on medium speed only until the cream holds a soft shape. When you can just begin to see traces the beater leaves in the cream, stop. The cream must not be stiff. Softer is better than too firm. If too firm, the chocolate will form flecks when folded with the cream.
13. In two small additions, fold about a third of the cream into the room-temperature chocolate, then fold the chocolate into the remaining cream. The mousse will be nice and thick and spreadable.
14. To assemble the cake. Remove the plastic wrap from the cake layer in the spring form ring and spread a generous 2 cups of the mousse onto the layer. Unwrap the remaining two cake layers and set one on top of the mousse. Press gently to level. Spread this layer with a generous 2 cups of mousse and set the last cake layer over the mousse. Press gently to level. Spread 2 cups mousse over the top cake layer. The spring form ring should be filled to the brim or slightly higher. Refrigerate the mousse cake and the leftover mousse (there’ll be about a cup) 6 hours or overnight.
15. For the ganache, heat the heavy cream and corn syrup in a small heavy saucepan over medium heat just until the cream comes to the simmer. Watch closely so it doesn’t boil over. Remove the pan from the heat and whisk in the chocolate until melted and smooth. Cool completely.
16. To complete the dessert. Heat a thin-bladed knife in hot water and shake off the excess water. Run the blade between the chilled cake and spring form ring to release. Repeat rinsing the blade in hot water as necessary. Unhinge the spring form ring and carefully lift it off the cake. With a narrow metal spatula, spread some or all of the leftover mousse on the sides of the cake, covering any bare spots.
17. Pour the completely cool ganache on top of the cake and spread it evenly with a large offset metal spatula right to the edges of the cake. It’s fine if some of the ganache runs down the sides of the cake.
18. Press reserved cake crumbs all around the side of the cake, coating it completely. Brush away excess crumbs. Refrigerate the cake to set the ganache. You can do this hours ahead.
19. To serve, rinse a sharp knife in hot water and shake off excess water before making each cut. Serve the cake as is or accompany each portion with a few raspberries. Refrigerate leftovers. This cake keeps well for 3 to 4 days.
Greg Patent is a James Beard Award-winning cookbook author for “Baking in America,” a food journalist, blogger and radio co-host for “The Food Guys” on Montana Public Radio. Please visit his blog, www.thebakingwizard.com, and follow him on Twitter and Facebook.