Mix 2 tbsps of mustard powder, 2 tbsps flour, 1/2 tsp salt and 2tsp sugar together. Blend with vinegar to make a smooth paste, and add 1 tbsp of very finely chopped herbs.
Use horseradish (hot!), marjoram, parsley, sweet marigold or sage.
Let mature for 2-4 weeks before using. Serve with appropriate meats.