Clean, wash and cut the rhubarb into pieces. Cut the vanilla pod lengthwise and scrape out the pulp. Boil up rhubarb, approx. 5 tbsp. water, vanilla pod and vanilla pulp in a pot. Simmer covered at low heat for 4-5 minutes
Stir starch and 2 tablespoons of cold water until smooth. Stir into the rhubarb and bring to the boil again. Season the compote with about 5 tbsp. sugar and let it cool down. Remove the vanilla pod
Stir curd and buttermilk until smooth. Stir in approx. 2 tbsp. sugar and lemon peel. Season to taste with lemon juice. Arrange buttermilk quark with some compote and decorate. Add the rest of the compote