Place 175g of sponge fingers in a serving dish (I use a 24cm x 16cm, 5-centimeter-deep dish), breaking them up and pushing them into any gaps to cover the bottom of the dish. Stir together 200ml of orange juice and 60ml of fino sherry, then evenly distribute over the sponge fingers. Cover and set the dish aside for 30 minutes.
Using a fork, puree 250 grams of raspberries into a thick purée, and then drizzle over the sponge fingers.
Put the egg yolks in the bowl of an electric mixer and the egg whites in a large mixing basin. Add 4 tablespoons of sugar to the yolks and mix with the whisk attachment until thick and creamy, then fold in 500 grams of mascarpone and a few drops of vanilla essence. Halt the mixing.
Beat the egg whites until they are thick, frothy, and nearly stiff. Now, integrate them into the mascarpone mixture with a large metal spoon.
Spread the mascarpone mixture over the crushed raspberries and sponge fingers, cover the dish once more, and refrigerate for at least a few hours, and ideally overnight. When ready to serve, whip 250ml of double cream and garnish with 150-200g of more raspberries. Serves 6 to 8
Fold the beaten egg whites carefully into the mascarpone mixture. You must ensure there are no visible egg whites, but take care not to overmix.
This tiramisu can be consumed within two hours of preparation, but it is much better if it is refrigerated overnight before the final cream and fruit layer is added. The longer the sponge softens in the fruit and alcoholic juice, and the longer the layers merge, the better.