For the chili mustard chutney, wash the chilies, remove the seeds and cut into small pieces. Peel and dice the onion.
Toast the mustard seeds in a small saucepan over low heat until they smell good. Add the sugar to the mustard seeds and let them caramelize slightly.
Now add all the remaining ingredients, except the water, to the saucepan and bring to the boil once briefly.
Turn down the heat, add the water and simmer for about 15 minutes, stirring several times.
Store the chili mustard chutney in a canning jar in the refrigerator and consume within 10 days.