Chop the dill tips. Heat the beef stock and simmer after adding 2 tbsp. dill tips for 10 minutes, then pour through a fine meshed sieve. Melt the butter, sauteé the onion cubes, dust with flour and continue to fry briefly. Pour in the strained dill stock, mix thoroughly (wire whisk). Add whipping cream and simmer uncovered for 12 minutes. Whisk with a stick mixer and then strain through a sieve. Stir in the sour cream and the remaining dills tips, season to taste with salt, paper, lemon juice and nutmeg.