Mix all ingredients really well and for a long time, or even better work with the hand blender. At least 10 minutes!
Cover with a kitchen towel and leave to stand overnight - the mustard only develops its characteristic taste with the oxygen from the air!
The next day, puree again well so that the herbs that have swollen in the meantime are finely chopped up. If necessary, correct the consistency with vinegar and wine - mustard flour sometimes absorbs more, sometimes less liquid.
Put in really well sterilized jars and store in a cool & dark place for about 3 weeks.