To make the pastry, put the flour and almonds in a bowl. Add the butter and rub in with your fingertips until the mixture resembles fine breadcrumbs. You can do this in the food processor. Stir in the sugar. Add the egg yolk and 1 tbsp of cold water and mix to form a firm dough. Knead briefly, then wrap in cling film and chill for 15-20 minutes.
Preheat the oven to fan 170C/ conventional 190C/gas 5. Roll out the dough and use to line a 24cm flan tin. Trim off the excess pastry, then line the pastry case with greaseproof paper and fill with baking beans. Bake blind for 15 minutes, remove the paper and beans and cook for a further 7-10 minutes until crisp and golden. Leave to cool.
To make the filling, melt the chocolate in a microwave on Medium for 2 minutes. Put the egg whites and sugar in a bowl over a pan of simmering water. Whisk for 5 minutes until thick, white and glossy. Remove from the heat and whisk for a further couple of minutes to cool it.
Whisk the cream until it just holds its shape. Fold the chocolate and cream into the egg mixture, then add the brandy. Pour into the pastry case and smooth the top. Chill until set for about 20 minutes.
To serve, whip the remaining cream until just stiff. Put a thin slice of tart on each plate. Spoon some cream on top and scatter with raspberries and blueberries. Dust with icing sugar.