Double Chocolate Stout Mousse Cake

I’ve been toying with the idea for a stout mousse cake for a couple of weeks now, and at first, I couldn’t get my head around how to make it happen. I didn’t know if stout mousse was even a thing, but I was sure if it wasn’t, it needed to be. It turns out there are a few stout mousse recipes online but they all seem best suited for a dessert glass. I needed a recipe that was stable enough to turn into a cake layer.

I finally knuckled down and figured out my own recipe based off another mousse cake on this blog.  I’m happy to say it worked, and my vision for this cake – realized!

This cake is delicious, too. The double chocolate stout gives the cake layer a richness that is nuanced with malt and hops. The light texture and flavor of the stout mousse on top is a nice contrast.  

Visually, the pale mousse on top of the dark chocolate cake reminds me of the froth that rises to the top of a freshly poured pint.

Any stout can be used, but I chose Fort Collins Double Chocolate Stout because it’s already a little sweet and has coffee-and-cream undertones. I think it’ll be a lot of fun to experiment with other kinds of stout in this cake, so don’t be afraid to get creative!

Double Chocolate Stout Mousse Cake

Yield: One 9-inch cake; serves 12

Prep: 1 hour 45 minutes plus more for chilling

Source: SprinkleBakes original recipe, cake portion adapted from Epicurious

[click for printable version]

The cake batter portion of this recipe makes a little more than a standard 9-inch cake pan can hold, so I suggest employing the use of a spring-form pan with tall sides -at least 9×3-inch. Or, you can divide the batter between two standard 9-inch cake pans and stack both layers on the bottom. The cake layers will need to be leveled with a serrated knife so the mousse can lay flat on top.

Chocolate
stout mousse

1/4 oz. package of powdered gelatin (about 2 tsp.)

2 tbsp. double chocolate stout

3 egg yolks

1/2 cup sugar

1/4 cup milk

1/4
cup chocolate stout

8 oz. white chocolate, chopped (Ghiradelli recommended)

1 1/2 cups whipping cream.

1. Sprinkle gelatin over 2 tablespoons stout in a small saucepan.  Let stand
   for 1 minute.  Whisk in egg yolks and sugar.  Whisk in milk and 1/4
   cup chocolate stout. Cook over medium heat, whisking constantly.  Mixture
   will thicken after 5 minutes or so.  When
   done, it should be thick enough to coat the back of a spoon.  Stir in
   chopped white chocolate and blend until chocolate has melted and mixture
   is well combined. Let cool.
2. Whip cream until stiff peaks form.  Gently fold whipped chocolate mixture
   into the whipped cream. Pour into prepared spring-form pan and smooth the top
   with a rubber spatula.  Place in freezer for a few hours or until mousse
   is frozen solid.

Chocolate
stout cake

1
cup double chocolate stout

1
cup unsalted butter

3/4
cup unsweetened cocoa powder

2
cups all-purpose flour

2
cups sugar

1/2
tbsp. baking soda

3/4
tsp. salt

2
eggs

1/2
cup plus 2 tbsp. sour cream

1. Preheat
   oven to 350 F. Grease and line a 9×3-inch spring-form pan with parchment.  Be sure to use a pan with deep edges, this
   recipe makes slightly more batter than one standard pan can hold.  Combine stout and butter in a large saucepan.
   Sift in cocoa powder and whisk to combine. Let cool slightly.
2. Whisk
   flour, sugar, baking soda and salt in a large bowl to blend; set aside.
3. Whisk
   eggs and sour cream into the cocoa/stout mixture.  Pour in flour and mix with an electric hand
   mixer until well combined.  Mixture will
   be thick.  Pour batter into prepared pan
   and bake for 35-45 minutes, or until a toothpick tester comes out clean.  Let cake cool in pan for 10 minutes then turn
   out and let cool completely on a wire rack. 
   Level top with a serrated knife or cake leveler.
4. When
   stout cake is completely cooled, remove frozen mousse from freezer and run a
   knife around the top edge.  Run a dish
   towel under hot water and wring out slightly; press hot towel around the edge
   of the pan for 1 minute so mousse will release easily.  Remove spring-form collar. Turn frozen mousse
   out onto the top of the stout cake. 
   Refrigerate until ready to frost.

 Chocolate
frosting:

1
cup unsalted butter, softened

4
cups powdered sugar

1/4
cup plus 2 tablespoons unsweetened cocoa powder, sifted

2
tablespoons double chocolate stout

Milk
or cream, optional

Chocolate
jimmies

1. Combine
   butter, confectioners’ sugar and 2 tablespoons cocoa in the bowl of a stand
   mixer.  Beat on low until just combined, and
   then add chocolate stout. Beat until light and fluffy.  If mixture is too thick to spread, add milk
   or cream 1 tablespoon at a time until consistency is reached.  Frosting should be a pale chocolate color.
2. Remove
   1/3 portion of frosting from the bowl and coat the top of the cake.  Beat additional 1/4 cup of cocoa into the remaining
   frosting until a consistent dark cocoa color is achieved.  Beat in milk or cream 1 tablespoon at a time
   if mixture is too thick to spread or pipe. 
   Transfer half the chocolate icing to a piping bag fitted with a large
   star tip. Frost the sides of the cake with the remaining frosting. Pipe stars
   around to top and bottom edge of the cake. 
   Sprinkle with chocolate jimmies.  
3. Keep cake refrigerated. Serve slices cold or at room temperature.

Cover the top first, then add more cocoa to the remaining frosting and cover the sides of the cake.