Grasshopper pie

For the base, melt the butter and dark chocolate and stir in the crushed biscuits.

Cool for a couple of minutes and then fold in the white chocolate pieces.

Spoon the crumbs into a 25cm loose-bottomed flan tin and press firmly along the bottom and up the sides. Chill in the fridge for 30 minutes to set.

Soak the gelatine in cold water for 10 minutes until soft, then squeeze out any excess water.

Put the gelatine into a bowl, set over a saucepan half-filled with hot water and heat gently until melted. Stir the gelatine into the sour cream.

Whisk the egg whites to stiff peaks. Add the sugar, 1 tablespoon at a time, and continue to whisk until stiff and shiny. Stir in the crème de menthe.

Fold the double cream into the sour cream and gelatine mixture, followed by the whipped egg whites.

Pour the mixture over the biscuit base and place in the fridge for several hours, until set.

When set, remove the mousse from the tin. Melt the dark and white chocolate in separate bowls placed over pans of simmering water. Cool slightly.

. Drizzle the melted white and dark chocolate over the top of the mousse and transfer to the fridge to set before serving in slices.