Essentially this is a sponge base, topped with chocolate mousse with a covering of dark chocolate glaze – a rich, indulgent cake (but cakes without at least those two qualities do not often qualify as cakes in my book!).
This is my attempt at recreating one of the cakes served there with an Afternoon Tea I enjoyed some time ago. For this cake, I use my version of a chocolate brownie base and a standard chocolate ganache-style glaze. The cake needs little, if any, decoration; a few drops of melted white chocolate or a sprinkle of dark chocolate shavings are sufficient.
I have made this a few times now, sometimes making one large cake and at other times cutting a larger rectangular cake into small squares, sometimes barely more than a mouthful in size, before glazing. And sometimes I have used a mirror glaze for a very shiny finish.
The mousse (which gets frozen) can be poured into either the same sized tin as the one the brownie is baked in or into a smaller tin (as in the recipe below); the latter will give an attractive “step” (as in the picture below) which looks attractive once it has been glazed.
Chocolate Mousse Cake: makes one 8″ cake
- 850g unsalted butter
- 850g dark chocolate (70% cocoa solids) or a mixture of milk and dark, broken into smallish pieces
- 50g chopped walnuts (or a mixture of nuts)
- 25g cocoa powder
- 25g plain white flour
- 1/2 teaspoon baking powder
- 84g golden caster sugar
- 2 medium free-range eggs, beaten
- 1 teaspoon best quality vanilla extract
- 165ml full fat milk
- 2.5g leaf gelatine
- 190g good quality milk chocolate, chopped into small pieces (or use a mix of milk and dark chocolate)
- 325g double cream
- 125g double cream
- 40g liquid glucose
- 100g best quality dark chocolate, finely chopped
- 1 tsp vegetable oil
- pinch of salt
You will also need an 8″ circular sandwich tin, lined with greaseproof to help remove the finished cake out of the tin.
For the brownie base:
(1) Preheat the oven to 160C(fan). Melt the butter and 100g of the chocolate together in a small bowl either over a pan of barely simmering water or in short bursts in the microwave (10-15 seconds at a time, wait a little, then repeat: once the butter has heated up and melted, you can stir the chocolate and it will melt quickly).
(2) Sift the flour, cocoa powder and baking powder together in a medium bowl. Stir in the sugar. Pour in the melted chocolate mixture, the eggs, walnuts and stir to incorporate fully. Stir in the dark chocolate chunks.
(3) Pour into the tin and bake for 15-20 minutes: it will have a nice crust but should feel soft underneath. Leave to cool fully in the tin before slicing.
(4) For the mousse: soak the gelatine in some cold water to soften for about 10 minutes. Meanwhile whip the cream to soft-peak stage. Bring the milk to the boil, remove from heat and stir in the gelatine until dissolved. Pour the milk over the chocolate and stir until melted. Leave until just cool and then fold in the cream until well blended. Pour into a 7″ round or square cake tin lined with clingfilm and freeze until solid.
(5) For the glaze: bring the cream and liquid glucose to the boil and add a pinch of salt. Pour over the chocolate and stir until melted and the mixture becomes smooth and glossy.
(6) Assemble the cake: turn out the mousse onto the brownie (as in the picture). You can trim around the edge or leave the wider brownie base which will form an attractive “step”. Pour over the glaze, ensuring it covers the mousse and any exposed parts of brownie. The glaze will start to set immediately as it touches the frozen mousse but transfer the cake onto a plate and place in the fridge to set fully – a couple of fish slices will help here – and the mousse will defrost in the fridge.