Wash the potatoes and cook covered for about 20 minutes. quench, peel and let cool down
Wash and peel the asparagus and cut off the woody ends. Cut asparagus into pieces and cook in boiling, lightly salted water covered with 1 teaspoon sugar for about 15 minutes. Remove from the stock and allow to cool
Mix yoghurt, salad cream, approx. 5 tablespoons asparagus stock, ketchup and brandy. Season to taste with salt and pepper. Cut potatoes into cubes. Mix carefully with asparagus, crayfish and cocktail sauce. Leave to stand for about 1 hour. Season and garnish with chervil
Drink: cool Riesling sparkling wine