For the cress soup, melt the butter, add the potato starch dissolved in water and cook gently for 2 minutes while stirring.

Add some of the chicken stock and keep stirring until the sauce is a little thick. Add the briefly washed cress and let everything simmer for 20 minutes, stirring occasionally. Remove from the fire and let cool down to room temperature, then chop in a blender.

Stir in the mascapone and season a little. Cover and let cool in the refrigerator. You can garnish the cold soup with a few cress leaves.