Chocolate-Chestnut Refrigerator Cake

Ingredients:
500 g (2 tins) Sweetened chestnut puree
175 g soft, unsalted butter
300 g dark chocolate, minimum 70%Cocoa solids
3 tablespoons dark rum/orange juice

To serve:

Creme fraicheCrystallised violets

Method:

Beat the puree in a bowl until it's smooth, and then add the butter,beating again to make a well-blended mixture.Melt the chocolate and let it cool slightly, before adding it to thechestnut and butter in the bowl. Beat in the rum, and spoon the chocolate mixture into a 23 x 10cm loaf tin, lined with clingfilm, in two batches, making sure the first layer reaches the corners and sides of the bottom of the tin before your smooth over the rest. Wrap the over-hanging clingfilm over the cake so that it is completely covered, and put it in the fridge to set for at least 4 hours, but a day or so in advance if you want.Don't take the loaf tin out of the fridge until you want to eat it, when you just unmould the cake, cut it into thin slices and serve with crème fraiche or sour cream.Makes 10 - 12 slices.(recipe by nigella lawson)