Wash and wipe the chilies and then chop into roundels.
In a pan dry roast fenugreek, mustard, fennel,cumin and Nigella seeds till they start giving a nice aroma.
Grind the roasted spices to make a coarse powder.
Heat mustard oil till it start to smoke and then let it cool down a bit.
Now add all the ground masala /roasted spice mix and the rest of the spicesand vinegar in the oil and mix well.
When the oil cool down completely then add it in the chopped red chilies and mix well.
Store in a glass jar and keep in sunlight for 4 days.
Start using after a week.
Serving- serve this pickle with poori ,paratha, khichdi, rice ,mathri etc.