Scrub the potatoes, wash them thoroughly, cut them in half and cook them in little boiling salted water for about 20 minutes. In the meantime wash the cucumbers and grate them into the quark. Peel and chop the onions.
Wash the tarragon and chop finely, except for something to garnish. Add onions and tarragon to the quark and mix everything together. Add milk and season with salt and pepper. Wash the lemon thoroughly, dab dry and finely grate the peel.
Arrange potatoes and curd on plates. Sprinkle with prawns and grated lemon peel. Serve garnished with lemon wheels and tarragon.