Chocolate Mousse Dome Cake with Hazelnut Crumb

For the chocolate cake: pre-heat oven to 325 F. (160 C). Line a baking tray (about 13 x 18 inches) with parchment paper.

Combine the flour, cocoa powder and baking powder together in a mixing bowl and set aside.

In a separate bowl, cream together the butter and icing sugar together until light and fluffy. Add the two eggs and beat until combined. Add half the dry ingredients to the mixture and beat, then add half of the buttermilk. Repeat with the remaining half of the dry ingredients and the remaining half of the buttermilk.

Spread the mixture on the prepared baking sheet and spread evenly using an offset spatula. Bake for 10-15 minutes until the cake is cooked through. Let cool then freeze until hard, approximately 30 minutes.

Cut out 6 rounds of cake measuring 2.75 inches in diameter and set aside in the fridge.

For the espresso bavarois: prepare a 1-inch diameter demi-sphere silicon mold.

In a small bowl, whisk together the sugar and egg yolks until pale yellow in color. Heat the cream over medium heat until it has come just to the boil. Reduce heat and gradually whisk in the egg yolk mixture until it thickens enough to coat the back of a spoon. If it appears that the eggs are starting to ‘scramble’ (curdle), then remove the pan for a few seconds from the heat as you continue to whisk. Once the mixture thickens, stir in the espresso (coffee) and let mixture cool to room temperature, then chill in the fridge.

Whip the 125 grams (1/2 cup) whipping cream to medium peaks. Once the espresso bavarois has cooled, fold the whipped cream into the bavorois, then spoon into the wells of the 1-inch demi-sphere mold. Level off the tops with an offset spatula and place in freezer until hard.

For the chocolate mousse: heat 120 grams of the whipping cream on the stove top over medium heat. Add the chocolate and sugar and stir until the chocolate melts. Remove pan from heat, then add the bloomed gelatin and stir until dissolved. Set aside to cool.

Meanwhile, whip the remaining 160 grams of whipping cream until firm peaks form. Gradually fold the cream into the cooled chocolate mix until combined. Pipe the mixture into the 2.75 inch demi-spheres until each well is half-full. Remove the frozen espresso bavarois demi-spheres from the freezer and unmold. Place one bavarois demi-sphere into each demi-sphere of chocolate mousse, with the flat side of the bavarois disc facing up. Press the disc down gently to ensure that it is positioned in the center of the mousse. Pipe the remaining chocolate mousse into the demi-spheres and smooth the tops with an offset spatula. Freeze until solid- approximately two hours.

For the chocolate mirror glaze: place sugar and water in a saucepan and set over medium heat until the sugar dissolves. Add the chocolate and stir until melted, then stir in the liquid glucose and remove from heat. Add the bloomed gelatin and cream and stir until well-combined. Pour the mixture through a fine sieve and let sit at room temperature for at least one hour until the mixture thickens.

For the hazelnut crumb: pre-heat oven to 180 C (350 F). Place hazelnuts on a lined baking sheet and roast for 10-15 minutes until golden. Remove from oven, place in a clean tea towel and rub to remove the skins. Place in a food processor and pulse until the nuts are finely ground.

Combine the ground hazelnuts, flour, sugar and butter in a bowl; rub the mixture together with finger tips until consistency of crumbs. Bake on a lined baking tray until golden (about 15 minutes)- stirring half-way through to ensure even baking.

To finish: Line a baking tray with plastic wrap and place a wire rack on top. Unmold the chocolate demi-spheres and place each one on top of a chocolate cake round. Place each cake on top of the wire rack and glaze each one with the chocolate mirror glaze. Let sit for a few minutes then transfer to a plate or clean tray; let sit in the fridge for about 30-60 minutes until each pastry has thawed a bit. Garnish each cake with a bit of grated orange peel on top to serve.