FOR THE CAKE
½ cup unsalted butter, softened
1+1/2 cup brown sugar
2 large eggs
½ cup half fat milk
½ cup Greek yogurt
1 tsp vanilla extract
2 cups + 2 tbsp plain flour, sifted
½ cup cocoa powder, sifted
1 tsp instant coffee granules
1 tsp sea salt
1 tbsp white wine vinegar
1 tsp baking soda
7oz good quality dark chocolate
2 tbsp dark brown sugar
1+1/2 tsp vanilla extract
2 cups heavy cream or whipping cream
3 tbsp chocolate strands
1 + ¼ cups chocolate curls
Preheat the oven to 375f/190c.
Butter three round 20cm (8 inch) diameter cake tins with removable bases and line the bases with baking parchment. Butter the paper.
Cream the butter and sugar together in a food mixer until light and fluffy and then stir in the eggs. Add the milk, Greek yogurt and vanilla extract and stir until combined.
With the mixer on low, slowly pour in the flour and then the cocoa powder, coffee granules and salt. Continue to mix until combined. Mix the white wine vinegar and baking soda in a small bowl (it will fizz), then stir into the mixture until thoroughly combined.
Divide the mixture between the three tins, smooth out the top with the back of a spoon and then bake in the oven for 20-25 minutes until an inserted skewer comes out clean.
Leave to cool in the tin for 10 minutes, then remove from the tins (discarding the parchment) and place on a wire rack to cool completely.
Now make the mousse – melt the chocolate with the sugar, vanilla and 2 tbsp of cream in a bowl, over a pan of simmering water (make sure the bowl isn’t touching the water). Stir until smooth, then take the bowl off the pan and set aside to cool for 10 minutes. Whip the cream until stiff peaks form and then slowly pour in the chocolate mixture whilst stirring until completely combined.
Now it’s time to assemble the cake. Place some baking parchment on a plate (or whatever you’re going to serve the cake from). I like to use two pieces of baking parchment lined up next to each other. This means it can easily be pulled away after decorating (just pull the two sheets apart – like a pair of curtains) – taking any mess with it. Place one cake on the plate and spread with 1/3 of the mousse. Top with the second cake and spread with another 1/3 of the mousse. Top with the third cake and spread the remaining mousse on top and round the sides of the cake.
Sprinkle chocolate strands on top of the cake (I just sprinkled them around the edge), and press the chocolate shavings into the side of the cake. Place in the fridge to set for an hour, and then serve.
The cake can be stored in a container in the fridge for 2-3 days.