Wash and clean the strawberries. Put 2 strawberries aside for decoration. Quarter the remaining strawberries. Wash lemon, peel thinly. Bring to the boil in a small pot with 350 ml currant juice, sugar and vanillin sugar and the cinnamon stick.
Mix cornstarch in the remaining juice and bind the boiling liquid with it. Boil up briefly while stirring. Remove lemon peel and cinnamon stick. Add strawberries to the groats and bring to the boil briefly.
Season to taste with cassis. Fill the fruit jelly into glass bowls and let it cool down. In the meantime, beat the egg whites for the snow dumplings until very stiff. Gradually add the sugar and the lemon juice.
Heat a pot with 1/4 litre water (the water should not boil). Cut off small dumplings with 2 teaspoons and put them on the hot water. Cover and leave to stand for 5 minutes. Put snow dumplings on the cooled groats.
Sprinkle with finely chopped pistachios and serve garnished with 1/2 strawberry each.