For the sambhar:
Clean fenugreek seeds powder. Take it in a big thali, mix turmeric powder, red chili powder, salt and asafetida. Mix castor oil ( do not heat) and mix the sambhar powder. Till the oil touches oneï¿½s hand. If you add, heated oil the sambhar becomes black. Prepare the pickle on the same day.
Wash dry mango first. For filling the whole mango; cut from the black side cut length and breadth wise to ½ of mango. Press and fill with the sambhar.
Take a big jar, and spread sambhar first. Over it arrange 2-3 layers of raw mango. Again put the sambhar. Repeat the process. On the top, spread sambhar powder. Clean the sides of the jar. Cover with a lid and tie with a cloth. Invert a pot over the jar. Next day, press the mangoes. Repeat the pressing for 3-4 days. Then pour oil, which is already be 2-3 inch above the raw mangoes.