The ingredients listed make a standard Bengali Five-Spice, but many cooks have their own recipe for this mixture. Sometimes celery seed is substituted for the mustard seed, or onion seed for the cumin. In Bengal, radhuni is often used instead of mustard seed, but this seed is hard to find outside India.
Mix all seeds together. For most recipes, add seed mixture to hot oil until they pop, then add other ingredients to spices. For making this spice blend for later use, toast seeds in a dry heavy skillet until they smell good. Cool and grind together.