Panch Puran- Bengali 5-spice mix:

Also known a Bengali Five Spice, this is a 5 spice mixture typical of Bebal. It consists of fennel seeds, mustard seeds, fenugreek seeds, cumin seeds and kalwanji (nigella) seeds in equal proportions.

In Bengali cuisine the panch puran is usually fried in a little oil or ghee until they start popping (almost immediately).
At this point. the vegetables or fish are usually added to alow them to become coated with the spice.
Panch puran is almost entirely used for cooking vegetables and fish, it is rarely used for meat.