250g dark chocolate, minimum 70% cocoa solids (I used three different bars for added depth of flavour)
125g unsalted butter
6 eggs: 2 whole, 4 separated
175g caster sugar
2 tablespoons Cointreau (optional)
Grated zest of 1 orange (optional)
For the cream topping:
500ml double cream
1 teaspoon vanilla extract
1 tablespoon Cointreau (optional)
Half teaspoon unsweetened cocoa powder for sprinkling
Preheat the oven to 180ºC/gas mark 4.
Line the bottom of a 23cm cake tin with baking parchment.
Melt the chocolate and butter together in a dish set over a pan of hot water. As it melts, in another bowl, beat the 2 whole eggs and 4 egg yolks with 75g of the caster sugar. When the chocolate and butter have fully melted gently add to the eggs with the Cointreau and orange zest.
In another bowl, whisk the 4 egg whites until foamy, then gradually add the 100g of sugar and whisk until the soft-peak stage. In small batches fold the egg whites into the chocolate mixture. Pour into the prepared tin and bake for 35-40 minutes or until the cake is risen and cracked and the centre is no longer wobbly.
Cool the cake in its tin on a wire rack. The centre with sink considerably as it cools.
Whip all the topping ingredients together until firm and stiff. Fill the centre of the cake, the holllow, and then dust with cocoa powder.