My Special Occasion Chocolate Mousse Cake

This post was originally on Honest Cooking, a new International cooking website, where I am a proud contributor! This is my post on my favorite special occasion cake, but be sure to check out the other great recipes and articles on food at HonestCooking!

This cake is an exquisite and luscious multi-layered cake that is near and dear to my boyfriend’s heart, as well as mine.

It's a simple devil’s food cake soaked (or sprinkled) with Chambord raspberry liqueur. It is then alternately layered with white chocolate, milk chocolate, and dark chocolate mousse, and topped with a rich espresso Mascarpone frosting.

The first time I made this cake it looked like a complete disaster. My boyfriend’s twenty-fourth birthday was rapidly approaching and I had ambitiously chosen to attempt an awe-inspiring dessert with twenty-four layers. It was my second time making a layered cake. However, I was fueled by my love for my boyfriend and was determined to make a great cake for my very first taste-tester and biggest supporter.

Admittedly, my ambitions were a little larger than my skills would allow. Or, rather, that gravity would allow. By the time I had reached the seventeenth layer, the cake was 12 inches tall and was starting to look like the tower of Pisa, so I decided to stop there. Besides, I was running out of mousse!

Luckily, the boyfriend was more than impressed with the cake, which his family devoured with gusto. It took only two days for me to get his text: “The cake is dead. Long live the cake.” Apparently, his entire extended family had started and ended the last four meals with a slice of cake each.

Since then, this cake has become my boyfriend’s absolute favorite cake of all time, and my go-to recipe for special occasions. So naturally, when he completed his Step 1 (an eight hour exam taken after the second year of medical school), I turned to this cake as a congratulatory gift.

I tried a different method this time; instead of using a cake leveler and cutting layers after baking, I baked thin layers one at a time so that the slices were pre-baked. This yielded much neater results, with minimal lopsidedness.

For his birthday, I had used cappuccino mousse in addition to the other layers of mousse in the cake, and simply alternated all of them over and over. On this particular occasion, I forgot to make the cappuccino mousse so instead I put it in the outer frosting. The first two times, I made a simple chocolate buttercream frosting for the cake but the flavor did not fit well with the rest of the recipe. The mousses are far too rich for your standard frosting and the buttercream added a cloying sweetness.

Instead, I combined mascarpone cheese and chocolate with espresso powder to produce one of the fluffiest most delicious frostings I’ve ever tasted. It has a hint of coffee that serves to bring out the flavor of the chocolate.

Needless to say, my boyfriend ate a slice every day for a week (it would have been two weeks, but his friends found out about it) and with every bite would exclaim, “this is the best cake EVER!” so I consider my job well done.

This is a really tasty and impressive dessert for special occasions and it’s worth busting out the fancy chocolate and cocoa powder for it. The best thing about this recipe is that it is open to many variations in flavors and textures, with endless possibilities.

I have used Duncan Hines’ Devil’s Food cake mix before to rave results, as well as this homemade recipe adapted from Thomas Keller's Bouchon Bakery. However, the store-bought mix tends to stay moister than any homemade cake. The assembly takes a bit of effort but if you’re only making one layer of each mousse, it won’t take long at all.

INGREDIENTS

• Devil’s Food Cake:
• 202 grams all-purpose flour (1 cup + 7 tbs)
• 62 grams unsweetened cocoa powder (1/2 cup + 4 tbs)
• 5 grams baking soda (1 tsp)
• 1 gram baking powder (1/4 tsp)
• 1/4 tsp kosher salt
• 2 large eggs
• 252 grams granulated sugar (1 cup + 4 tbs)
• 2 tsp vanilla extract 
• 172 grams mayonnaise (plain, full-fat) - 1/2 cup + 5 tbs
• 210 grams water, at room temperature (1/2 cup + 6 tbs)
• Mousse
• 6 oz milk chocolate chips + 8 oz heavy cream
• 6 oz dark chocolate chips + 8 oz heavy cream
• 6 oz white chocolate chips + 6 oz heavy cream 


• Frosting
• 1/3 cup (33g) natural unsweetened cocoa powder
• 1 TBS instant espresso powder
• 1 ½ cups (365g) chilled heavy whipping cream
• 1 1/3 cups (250g) sugar
• 2 8-ounce containers (454g) of chilled mascarpone

INSTRUCTIONS

1. Preheat oven to 350 degrees F or 170 degrees C.
2. Butter/grease or put down parchment paper on one square pan 8x8 inches.
3. Whisk the eggs and sugar until well combined.
4. Add in all the rest of the ingredients and gently whisk (or use a spatula) to stir it all together until combined.
5. Pour the batter into the pan and bake for about 35-40 minutes or until you insert a toothpick or knife in the center and it comes out clean.
6. OR
7. Scoop a small amount of batter into the cake pan, making a simple thin layer. If you prefer, measure out the batter to ensure even layers…I used about 1 cup of batter for each layer (I had two slices left over that were too crumbly so I made cake balls out of them instead).
8. Wrap a wet baking strip or wet towel around the pan to ensure easy removal.
9. Bake for about 10-15 minutes or until a cake tester comes out clean.
10. Let cool before turning over onto parchment paper. 
11. Repeat until the batter is finished.
12. Place the layers in the freezer with parchment paper between each until chilled.

For the Mousse

1. Heat each set of heavy cream (8oz at a time) in a small saucepan (alternatively you can heat all the cream at once in a large saucepan, but I'm not good with keeping an eye on that before it overflows)
2. Set each type of chocolate in 3 separate heat-safe bowls.
3. Once the cream starts to boil, pour over the chocolate in the bowl and let the chocolate be completely submerged.
4. Let sit for a minute and then gently whisk until combined.
5. Cover with wrap, and chill for at least 2 hours or overnight.
6. Beat the white chocolate with an electric beater on medium until fluffy.
7. Do not over mix as it will curdle!
8. Beat the milk chocolate mousse on low until fluffy, it will thicken faster than the white chocolate.
9. No need to use an electric beater for the dark chocolate, it should be thick enough to spread. Let it come to room temperature before spreading.
10. Chill until ready to use.
11. Repeat with each set of chocolate chips.

For the Frosting

Add the espresso powder to the cocoa powder. 
Bring 1 cup of heavy whipping cream to a boil in a small saucepan. 
Slowly pour the cream over the cocoa mixture, whisking until the cocoa/espresso is completely dissolved. 
Add the sugar, and when dissolved, add in the remaining ½ cup heavy whipping cream.

Chill in the fridge until cold, at least two hours or overnight.

Use an electric beater on low or medium to beat the mixture until it thickens.

Add in all the mascarpone and beat on low until well-combined (mascarpone can curdle quickly so be gentle). You can use a whisk for this as well.

Assembly

1. Spread Chambord or liqueur of your choice over a layer of cake before spreading on the mousse. I put in about a tablespoon on each slice.
2. Spread the mousse evenly on top of the layer and top with another slice.
3. Repeat until finished.
4. Frost with the mascarpone espresso frosting.