Chocolate Decadence Cake

I definitely inherited my love of chocolate from my dad– he’s a huge fan of chocolate, the darker the better, and back when the extra-dark chocolates weren’t widely available I remember him melting semisweet and unsweetened together to make his own bittersweet chocolate blocks, which he kept in the freezer and which I totally never pilfered for snacks… (whistles innocently)

In any case, when his birthday comes around, that’s my excuse to come up with rich, dark, decadent chocolate cake, the blacker the better. Having gone through the standard flourless chocolate cake recipes, a recipe involving layers of whipped and melted ganache, and an extremely dark chocolate ice cream (caused by my inadvertently doubling the amount of cocoa I was supposed to use… it was fabulous), this year I wanted to try something a little different.

This creation isn’t exactly a cake– or rather, it’s not just a cake. It’s really a combination/adaptation of three recipes I’ve had on the blog before– the basic chocolate cake, the nutella crunchies, and the easiest chocolate mousse ever. But they combine to make a fabulous amalgamation of flavors and textures that is a one-of-a-kind chocolate experience.

Cake base (make 1 day ahead, or make way ahead and freeze)

Makes one thin 9″ cake layer

1 1/2 cups flour
1 cup sugar
3 tbs. unsweetened cocoa
1 tsp baking soda
1/2 tsp salt
1 tsp vanilla extract
2 tsp. vinegar
1/4 cup vegetable oil
1 cup cold water
1 tsp. coffee powder

1. Preheat the oven to 350F. Grease a 9-inch round pan, and line with a circle of parchment paper.

2. In a large mixing bowl, mix flour, sugar, cocoa, soda and salt. Make three wells in the flour mixture.

3. In one well put vanilla; in another the vinegar; and in the third the oil.

4. Dissolve the coffee powder in the cold water (or just use cold coffee) and pour the water over the mixture. Stir until smooth.

5. Pour into the pan and bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean.
6. Cool in the pan for 15 minutes, then remove to a rack to cool completely.

 

Ganache layer (make up to 1 week ahead)

6 oz dark chocolate, chopped

5 oz heavy cream

1. Heat heavy cream in a microwave-safe measuring cup until it just barely starts to bubble.

2. Pour over chopped chocolate and let sit for 2 minutes. Stir until smooth.

3. Refrigerate until cool, but still of pouring consistency. Alternatively, store in the refrigerator, covered, for up to 1 week and re-warm just to room temperature when ready to pour.

Crunchy layer (make up to 3 days ahead)

120g dark chocolate, chopped (about 4 oz)

160g Nutella (about 2/3 cup)

100g cornflakes (about 4 cups)

1. Place chopped chocolate in a microwave-safe bowl and heat for 30 seconds at full power. Stir, and heat for another 30 seconds.

2. Add Nutella and stir, then heat for a final 30 seconds. Stir until completely smooth.

3. In a large bowl, crunch the cornflakes up with your hands just a little so the flakes aren’t too large. 4-5 good scrunches should do it.

4. Pour melted chocolate/Nutella over the cornflakes and stir to coat.

5. Immediately press the mixture into the bottom of a 9″ round springform pan lined with a parchment round. (Mine was also lined with a parchment collar, see Note 1)

6. Spread half of the chocolate ganache over the crunchy layer, and immediately press the cooled cake layer into the ganache.

Mousse layer and assembly

12 oz. semisweet or bittersweet chocolate, chopped

9 oz. milk

1. Combine chocolate and milk in a saucepan and stir over low heat until smooth.

2. Empty a tray of ice cubes into a large mixing bowl and add water to make an ice bath. Nest a smaller metal mixing bowl inside, touching the ice cubes. Pour your melted chocolate mixture into the smaller bowl, and use an electric mixer to whip until thick (abut 3 minutes). It should look like pudding. Don’t overwhip or it’ll be grainy and too firm to spread.

3. As soon as it’s ready, pour the mousse over the cake layer and spread it carefully to the edges of the pan. Refrigerate for at least 1 hour.

4. If necessary, re-warm the ganache until just pourable. Pour over the mousse and refrigerate again for at least 2 hours. Remove from the refrigerator about 20 minutes before serving.

5.  Unmold and slice with a sharp knife dipped in hot water.

Notes:

1. I added a parchment collar to my springform pan because I wasn’t sure if the pan would be tall enough to contain the mousse and ganache layers. The pan ended up being just tall enough after all, but in the future I would still do a shorter collar to assist in ease of removal.
2. The mousse can go from perfect to overwhipped/overchilled in a matter of seconds, so make sure you are ready to pour the mousse onto the cake as soon as it’s ready. If it firms up too much, just dip the bowl into a larger bowl of warm water and mix it all up again with your beater until it smooths out. Unlike overwhipped cream or overwhipped egg whites, you can re-melt and re-whip this mousse with no trouble.
3. Also on the mousse I would strongly recommend using semisweet (no more than 56% cocoa solids) chocolate, rather than the higher percentage bittersweet stuff. I used bittersweet and it was just a bit too acidic for me, in addition to setting up more firmly than I’d have liked. I think semisweet would be better in flavor and in texture.
4. The crunchy layer is kind of hard to cut through– make sure you use a large, sharp knife and do it on a cutting board if possible.