Preheat the oven to 180C and line a baking tin with greaseproof paper.
In a heatproof bowl, melt the chocolate and butter, either in the microwave or over a pan of simmering water. Set aside to cool.
In a large bowl, mix the flour, cocoa powder, sugar, baking powder and bicarbonate of soda.
Once the dry ingredients are all mixed together, slowly add your eggs, oil and milk and mix thoroughly.
Pour the cake mixture into the cake tin and bake for 35-40 minutes.
Whilst the cake is baking, make a shot of espresso and set aside.
To make the cream filling, whisk the mascarpone first, then gradually add the double cream to ensure the filling is smooth.
Once the cake has baked and cooled, use a pastry brush to gently soak the cake layers in the espresso.
Using a piping bag, pipe the cream filling around the edge of the cake and then the centre.
Assemble your cake and spread the remaining cream across the top of the cake.
Finish with a light dusting of chocolate powder and enjoy!
