Chop the mangoes in 1.5 inches pieces. and add them in a bowl. Discard the stones but do peel off the flesh from the stones if any. No need to remove the outer skin of the mangoes if they are soft and tender.
Take the chopped mangoes in a large non-reactive mixing bowl.
Now first add the ground fenugreek seeds and mustard seeds.
Then add fennel seeds, nigella seeds, turmeric powder and red chilli powder and salt.
With a steel or wooden spoon, mix very well so that the spices uniformly coat the mango pieces. Check the taste of the pickle masala mixture or 1 to 2 mango pieces. The taste should be slightly salty. If not, then add some more salt.
Next pour ½ cup of mustard oil.
Mix very well.
Spoon the prepared pickle mixture in a cleanceramic jar or glass jar. Use a clean spoon
Cover with lid and keep in sunlight for 3 to 4 days. Note that the sunlight should be very good with the strong sun rays falling on the pickle jar. It should not be cloudy or dark.
Everyday after sun-drying in the evening, open the lid and give a gentle mix to the pickle with a clean spoon. Take the mango pieces settled at the bottom upwards in the jar and give a thorough mix. Basically mixing and tossing that needs to be done. Do this everyday.
In the evening, get the jar inside and keep in a cool dry place. Next morning again keep in the sunlight.
After keeping in the sunlight for 3 to 4 days, add the remaining 2.5 cups mustard oil. Again with a clean spoon mix very well. The oil should seep inside in the jar and reach the bottom of the jar too. You want all the mango pieces to be surrounded with some oil.
Note that you do not need to heat the mustard oil. You can add more mustard oil if required. Do note that the mustard oil should float above the pickle by 2 to 3 inches Always remember to keep the oil floating above the pickle.
Seal with the lid keep in a cool dry place for 4days till everything gets mellowed and pickled. Initially you may find a slightbitter taste in the pickle, but after 6 to 7 days, the bitterness will go away.This punjabi mango pickle stays good for a year at room temperature withoutrefrigeration
Enjoy this Punjabi mango pickle with any Indian meal.