Chocolate Brownie Mousse Cake

Ingredients

Brownie Layer

• 1/3 cup / 83 g unsalted butter, cut into cubes
• 1/2 cup / 100 g dark cooking chocolate, (see notes)
• 1/2 cup / 75 g all-purpose flour
• 2 tbsp / 16 g Dutch process cocoa powder, sifted (see notes)
• Pinch of salt
• 2 large eggs, room temperature
• 1/3 cup / 70 g 70g caster sugar, (superfine)
• 1/3 cup / 65 g brown sugar
• 1 tsp vanilla extract
• 1 / 20 ml coffee shot

Chocolate Mousse Layer

• 3 cups / 630 g dark cooking chocolate
• 3 large eggs, separated
• 2 gelatin leaves, platinum strength or above (see notes)
• 1 3/4 cups / 440 ml heavy cream, cold
• 1 tsp vanilla extract
• 1/4 cup / 55 g caster sugar

Instruction

Brownie Layer

1. Preheat a fan forced oven to 160C/320F (170C/340F for no fan). Line the bottom of an 20cm / 8-inch springform pan. Set aside.
2. Add the chocolate and butter to a heatproof bowl and microwave for 30 seconds at a time, stirring each time until melted. Alternatively, you can do this using a double boiler. Set aside to cool slightly.
3. Add the flour, cocoa powder and salt to a small mixing bowl and use a whisk to combine.
4. To a large mixing bowl, add the eggs, both sugars and vanilla extract. Use an electric hand mixer to whisk until pale, fluffy and doubled in volume, about 2-3 minutes.
5. Add the coffee shot and mix until combined. Next, add the cooled chocolate mixture and whisk until well combined. Use a spatula to scrape the bowl down.
6. Add the dry ingredients and fold using the spatula until no dry ingredients are showing. Add the mixture to the springform pan and bake for 15 minutes. Once baked, allow to cool completely at room temperature. Carefully run a knife around the edge of the brownie to loosen from the springform pan. Clean the inside of the springform pan. Place a piece of baking paper on bottom and place the sides on top. Clip to tighten.
7. Spray the side of the pan with oil spray and place a large piece of acetate measuring 65cm (26-inches) in length on the inside. The oil will help it stick to the pan. Place the cooled brownie in the pan and set aside.

Mousse Layer

1. Chocolate – Add the dark chocolate and 3/4 cup (185ml) heavy cream to a heatproof bowl over a double boiler. Stir until melted. Take off the heat and add the egg yolks, mix using a spatula until combined. Keep the double boiler set up on the stove.
2. Add the gelatin leaves to cold water and allow to soak for 5 minutes. Once bloomed, take out of the water and squeeze excess water out. Add to the chocolate mixture and stir until gelatin is melted. Set aside to cool slightly.
3. Whipped Cream – Add the remaining 1 cup (250ml) of heavy cream and 1 tsp of vanilla extract to a medium sized mixing bowl and whip using an electric hand mixer until you reach stiff peaks. Set aside in the fridge until ready to use.
4. Swiss meringue – Add the egg whites and sugar to a large heatproof bowl and place on top of a double boiler. Whisk for 5 minutes or until the sugar has dissolved completely. You can test this by feeling it in between two fingers.
5. Take off the heat and allow to cool for 10 minutes. Use an electric hand mixer to whisk until the mixture doubles in size and becomes thick and glossy.
6. To complete the mousse, add half the meringue to the chocolate mixture and gently fold through using a spatula until well combined. Add the remaining meringue and the whipped cream and fold through until evenly combined.
7. Pour the mixture on top of the cooled brownie layer and spread around as evenly as you can. Chill in the fridge overnight. This needs a good amount of time to set properly.
8. To remove from the pan, run a knife under hot water and dry. Run it around the top of the mouse layer before loosening it from the springform pan. Carefully lift up the sides of the pan. Gently unwrap it from the acetate and slice to serve.