Melt the butter in a pan. Add the blueberries without defrosting and steam for 3-4 minutes, turning. Sprinkle berries with 1 tbsp. sugar, caramelise briefly, deglaze with vinegar, pour into a bowl and allow to cool. Cut open the vanilla pod and scrape out the pulp.
Use the pod for other purposes. Mix quark, 3 tablespoons sugar, oil and vanilla pulp. Whip cream until stiff and fold in. Arrange quark and blueberries in bowls
Waiting time approx. 25 minutes