It's available in Indian markets. It's darker and sweeter than ordinary cumin. To bring out its nutty flavor, it helps to toast the seeds briefly before using them. Look for this in Indian markets or health food stores. Pods of this spice are sold in Indian markets.
Some recipes call for the entire pod to be used, others call for the ground seeds.
These are smaller and hotter than the yellow mustard seeds that most western cooks are familiar with. Look for this in Indian markets. OR yellow mustard seeds carom seed See ajwain . It's available as seeds or powder, and you can usually find it in Indian and Middle Eastern markets. If it's not available, just leave it out of the recipe.