Finely dice the toast. Cut the vanilla pod in half lengthwise and scrape out the pulp. Drain curd well. Mix toast, egg white, quark, vanilla pulp, lemon peel and a few drops of sweetener. Let rest for about 10 minutes.
Cut strawberries and rhubarb into small pieces. Steam the rhubarb and half of the strawberries in 5 tablespoons of water for 3-5 minutes
Fold in remaining strawberries and season the compote with sweetener and some lemon juice
Form 2 dumplings from the curd mixture with lightly floured hands. Let them simmer in plenty of boiling salt water for about 10 minutes. Serve with rhubarb compote and pistachios
The quark dumplings also taste very good when fried, for example the next day. It is best to prepare two portions at once