Step 1

Line the base of a 20cm spring form cake tin with baking parchment.

Step 2

Place the shortbread biscuits in a food processor and whiz to make fine crumbs. Add the melted better and mix well. Press into the base of the prepared tin and chill for 30 mins while making the topping.

Step 3

Place the gelatine leaves in a bowl with 3 tbsp cold water and allow to soften for 10 mins. Meanwhile warm the double cream in a small pan, but do not boil. Remove the gelatine from the water and place in the cream, stir until dissolved.

Step 4

Chop the chocolate and set aside 100g. Melt the remaining 300g chocolate in a bowl over a pan of gently simmering water. Mix the soft cheese with the mascarpone. Fold the melted chocolate, the cream and gelatine mixture and the liqueur into the cheese mixture. Whisk the egg white until it forms stiff peaks, then fold into the chocolate mixture with the remaining chopped chocolate. Spoon into the tin, level the top and chill overnight.

Step 5

When ready to serve, run a hot cloth around the edge of the tin to loosen, then transfer the cake to a flat plate. Decorate with chocolate curls