- 600g unsalted butter, at room temperature
- 400g caster sugar
- 450g soft light brown sugar
- 6 large eggs, beaten
- 2 tsp vanilla extract
- 700g plain flour
- 4 tsp baking powder
- 2 tsp bicarbonate of soda
- 200g cocoa
- pinch of salt
- 300ml buttermilk
- 300ml boiling water
- 150g dark chocolate, finely chopped
- 170ml double cream
- 20g unsalted butter
- 20g caster sugar
- Preheat the oven to 160°C/325°F/ Gas Mark 3
- Cream the butter with both of the sugars until pale and light, this will take 3-4 minutes in a free-standing mixer.
- Gradually add the eggs, mixing well between each addition and scraping down the sides of the bowl from time to time. Add the vanilla extract.
- Sift the flour, baking powder, bicarbonate of soda, cocoa and pinch of salt into the mixture and mix until almost combined. Add the buttermilk and boiling water and mix until smooth.
- Divide the cake batter between 2 x large hemisphere pans ( 20cm) and bake on the middle shelf of your preheated oven for about 2 hours until well risen, firm and a wooden skewer inserted into the middle of the cakes comes out clean.
- Cool the cakes in the tins for 2-3 minutes then carefully turn out onto a wire cooling rack leave until cold. Meanwhile, prepare the Ganache.
- Put the chocolate into a bowl.
- Put the cream, butter and sugar in a small saucepan and heat until just boiling.
- Pour the cream mixture over the chocolate and leave for 5 minutes until the chocolate has melted.
- Stir until smooth then set aside until thick enough to spread.
Assemble the cake
- Place the first cake layer on a serving plate and using a palette knife, spread with ganache.
- Top with the second cake layer and gently press the layers together.