Wash the chillies and dry completely.
Remove the stem and make a slit in the middle. Remove seeds and cut in half if preferred. Set aside.
Dry roast cumin, coriander and fennel seeds until it omits aroma. (about less than 2 minutes).
Remove in a plate and let it cool completely.

In the same pan add oil and heat. Set aside.
In a grinder jug pulse the roasted cumin, fennel and coriander seeds until it is coarsely ground. Remove in a bowl.
Pulse the flaked mustard seeds couple of times. Remove and add it to the fennel mix. Add salt, 1/2 teaspoon turmeric, asafoetida, 1/2 of the oil and lemon juice. Mix well.

Fill the red chillies with mix and put it in a jar. Add the rest of the oil and close the lid of the jar. Shake it couple of times so all the chillies are covered in oil.
Leave it for 3 days to marinate. Enjoy red chilli pickle with your meal.
This can be stored for 3 months.