Wash and sort the berries. Strip the currants from the panicle with a fork. Clean the gooseberries. Mix the berries, 50 g sugar and grappa in a bowl, then place in 1 large or 2 small casseroles.
Beat the egg whites until stiff, adding 175 g sugar. Fold in vinegar. Spread the beaten egg whites in large blobs on the berries. Bake in the preheated oven (electric cooker: 150 °C/ convection oven: 125 °C/ gas: level 1) for about 50 minutes.