For spices: Heat a pan and roast whole spices such fennel seeds, fenugreek seeds and cumin seeds. Stir and slightly roast the spices for upto 2 minutes. Turn off flame, keep to cool.
Take oil to be added to pickle heat it up well in a pan. Oil has smoked up rightly, turn off flame. Let oil cool.
As the whole spices cool down, add plain salt too,then coarsely grind in mixer jar. Keep grinded spices in plate. Coarsely grind black mustard seeds separately, put over the grinded spices.
Add the rest of the spices such as black salt, turmeric powder, asafoetida and Dry mango powder in the spices. Add 2 tbsp oil from pan to the pickle and mix it.
To cut chilies: Remove stalk from chili. Slit the chilies from the center vertically, take out seeds and pulp from it. Prepare all chilies likewise.Put the seeds from the chili in the spices mix if you want.
To Fill the chili with spice mix: Take chili, open it. Stuff the chili with the prepared spice mix. Press well with spoon remove extra stuffing. Keep the stuffed chili in plate. Fill all likewise.
Take out the oil in a bowl. Dip each stuffed chili in oil and take out, keep it in a separate bowl.Fill up the sterilized container with the stuffed chili pickle. Put the leftover spice over the chilies, pour oil over them, then close lid of container.
After 3 days, the pickle will soak the spices and will be ready to eat. If you want to keep it for a longer duration, then as it settles after being soft after the 3 days time. Then fill the container with hot oil so that the pickle is completely submerged. By making it this way you can relish it for a year.