Chocolate slices

Line a 22 x 11 cm loaf tin with plastic wrap. Beat the butter and sugar together until light and fluffy. Add the egg yolks one by one, beating well after each addition. Melt the chocolate in a glass bowl over boiling water or in the microwave oven on 100 per cent power for 1 or 2 minutes. Stir every now and then. Add a little of the butter mixture to the melted chocolate and mix. Add the chocolate to the remaining butter mixture and mix well. Add the biscuit pieces and the brandy or whisky. Whisk the egg whites until stiff and fold into the mixture. Turn into the loaf tin and freeze until set. Cut into slices and serve.