Step 1: Peel the oranges using a sharp knife, ensuring all the pith is removed. Slice as thinly as possible and arrange over a dinner plate. Sprinkle with the demerara sugar followed by the Grand Marnier and set aside.

Step 2: Crumble the Christmas pudding into large pieces and scatter over the bottom of a trifle bowl. Lift the oranges onto the pudding in a layer and pour over any juices.

Step 3: Beat the mascarpone until smooth, then stir in the custard. Spoon the mixture over the top of the oranges.

Step 4: Lightly whip the cream and spoon over the custard. Sprinkle with the flaked almonds and grated chocolate. You can make this a day in advance if you like, chill until ready to serve.