1. Heat the oven to 150C/300F/Gas Mark 2

2. Draw a 23cm circle on 2 sheets of baking parchment and place on baking sheets.

3. Whisk the egg whites until stiff, then whisk in half the sugar and the vinegar until glossy and stiffly peaking.

4. Stir the cornflour into the rest of the sugar and fold into the meringue with the chopped chocolate. Spoon the mixture onto the two circles and spread evenly.

5. Bake for 1 hour, remove from the oven and cool.

6. Put the chestnut puree into a bowl, add the brandy or rum, icing sugar and beat until smooth, stir in the ginger. Whip the cream until almost stiff then fold into the chestnut mixture.

7. Carefully remove the meringues from the paper, place one on a flat plate and spread over half of the chestnut cream. Place the other meringue on top and spread over the remaining chestnut cream. Finish by scattering the grated chocolate over the top.

Variation: extra whipped cream can be piped around the top edge of the meringue before adding the grated chocolate. Instead of using grated chocolate, chocolate curls can be used to decorate the top.