Before you begin, take the spices and salt in small bowls and keep them in sunlight for 1 to 2 hours. Know the spices, swipe up!
Take fenugreek seeds and mustard seeds in a dry grinder jar or a spice grinder.
Grind the spices to a coarse mixture.
Rinse and wipe unripe green mangoes.
Chop the mangoes to 1.5 inch pieces. Know more about this step, swipe up!
Take chopped mangoes in a large steel or glass mixing bowl.
Add the ground fenugreek seeds and mustard seeds mixture.
Add the remaining spices - fennel seeds, nigella or onion seeds, turmeric powder and red chili powder.
Add salt to the mangoes.
With a steel or wooden spoon, mix well so that the spices uniformly coat the mango pieces. Add more salt, if the taste is not slightly salty.
Next, pour the mustard oil.
Mix the spices and the oil with the mangoes very well.
Spoon the mango pickle in a clean ceramic or glass jar.
Seal the jar with a lid and keep in sunlight for 3 to 4 days.
Everyday after sun-drying, open the lid, mix and toss gently with a clean spoon. This pic is of the first day.
By the third day, you'll see the oil floating.
This is the pickle after mixing, on the fourth day.
On the last day, pour some more mustard oil in the jar.
With a clean spoon, once again give a thorough mix. The mustard oil should float 2 to 3 inches above the pickle. Seal and keep in a cool, dry place for 4 days more or till the pickle is ready to eat.