Wash the herbs, roughly chop them and finely puree them in a blender or with a hand blender with 500 ml of water and a large pinch of salt. Add 500 ml yoghurt and possibly a few ice cubes and mix again briefly. Fill into 5 glasses, garnish with freshly ground colored pepper and serve immediately.
If there is no herb mixture available for Frankfurt Green Sauce, you can put together the following herbs yourself: borage, chervil, cress, parsley, pimpinelle, sorrel and chives.