Step 1

Heat oven to 180C/fan 160C/gas Butter and line the base of a 20cm round cake tin. To make the cake, break up the chocolate and put in a small bowl with the coffee over a pan of water. Heat gently, stirring a little, until the chocolate has melted and you have a smooth sauce. Set aside.

Step 2

Beat together the butter and sugar in a large mixing bowl, using an electric hand whisk or wooden spoon, until the mixture is light and fluffy. Beat in the eggs, a little at a time. Don’t worry if the mixture curdles, it won’t affect the finished cake. Fold in the chocolate, then the hazelnuts, then sift in the flour and baking powder.

Step 3

Pour the mixture into the cake tin and bake for 45-55 mins, until firm to the touch. Cool in the tin for 5 mins, then turn out and cool on a wire rack.

Step 4

To make the filling, put the chocolate, butter, coffee and cream in a small pan and heat gently, stirring until dissolved and smooth. Remove from the heat and stir in the icing sugar. Leave to cool, then put in the fridge, stirring occasionally until it is spreadable. This will take 1-2 hrs.

Step 5

Slice the cake in two horizontally and put the base on a serving plate. Spread over half of the filling and scatter over half the hazelnuts. Cover with the top of the cake and spread the remaining filling over the top. Scatter the remaining hazelnuts around the top edge of the cake.