Step 1

Rinse a 22 x 10 x 7cm deep loaf tin (about 1.5 litres in volume) with cold water, but don’t dry it. Line the tin with cling film, smoothing out as many of the wrinkles as you can.

Step 2

Stir the chocolate, chestnut purée and amaretti biscuits together, then stir through the orange and zest. Gently fold in the cream until combined, then spoon the mixture into the tin. Smooth the top and cover with cling film. Freeze for 3-4 hrs until just firm.

Step 3

Take the parfait out of the freezer 20 mins before serving. To serve, dip the tin briefly in hot water, then turn out onto a serving plate and remove the cling film. Scatter over the grated chocolate and slice.