Chocolate Lamington Sponge Roll

Whisk together the cream, mascarpone, and icing sugar to medium firm peaks. Unroll the sponge (but keep it on the wrapping paper it came with) and use a palate knife to spread the jam over the sponge. Add the cream mix, leaving a 2cm gap at the edges. Carefully roll back up and refrigerate for at least an hour to let the cream set. Meanwhile, make your icing. In a pan or microwaveable jug or bowl, put the icing sugar, cocoa, milk, and butter. Microwave or heat for 1 minute, then whisk until smooth. If the mix seems too thick add a little hot water or extra milk to the sauce - it needs to be thick enough to spread over the sponge.

Remove the sponge roll from the wrapping paper and put onto a rack over a baking tray. Pour over the icing and spread with a spatula. Sprinkle over the coconut (you may need to press it into the sides).

Allow the icing to set for at least 30 minutes before slicing.