1Wash and dip the unripe mangoes in water for 1 hour. Then wipe them well to remove any excess water.
2Remove the top and peel the mangoes. Chop them into small pieces, making sure not to cut into the pit.
3In a pan, heat whole coriander, fennel seeds, cumin, mustard seeds, black pepper, and fenugreek seeds on low flame. Do not roast; just heat until fragrant. Turn off the heat.
4Transfer the lukewarm oil to a clean and dry bowl.
5Add turmeric powder, Kashmiri red chili powder, asafoetida, nigella seeds, and the crushed spices to the bowl.
6Add the chopped green chilies and the chopped mangoes to the bowl. Mix well. Add salt to taste.
7Heat a coal and add some oil and asafoetida to it to create smoke. Place a glass jar on top of the coal to infuse the pickle with smoky flavor.
8Add the prepared pickle mixture into the jar. Cover with a cloth or half-open the lid and keep in sunlight for 3-4 days. Shake once a day to ensure even distribution of oil. To extend shelf life, consider adding vinegar.