Coffee mascarpone cake
You will need 2 x 18cm (7in) diameter cake tins. Preheat the oven to 180°C, 350°F, Gas 4, then butter the sides of the cake tins, dusting them lightly with flour, then lining the base of each tin with a disc of baking parchment.
Cream the butter until soft in a large bowl or in an electric food mixer. Add the caster sugar and beat until the mixture is light and fluffy.
Gradually add the beaten eggs and the Irel coffee essence to the creamed butter and sugar mixture, beating all the time. Sift in the self-raising flour and fold it in gently to the cake mix. Divide the batter between the two prepared tins, making a slight hollow in the centre, so they will rise with a flattish top.
Put the tins in the oven and bake for about 20 minutes, or until well-risen, golden brown and springy to the touch. Remove from the oven and allow the cakes to sit in the tins for 10 minutes.
Loosen around the edges of each cake using a small, sharp knife, then carefully remove the cakes from the tins and leave them on a wire rack to cool completely.
Meanwhile, make the icing. Place the mascarpone cheese in a bowl, and mix in the icing sugar, along with the Irel coffee essence.
Place one of the cakes upside down on a plate, then spread half the icing over it. Put the other cake, right side up, on top of the filling, then spread the rest of the icing on top and dust with the cocoa powder, if you're using it.