What Does It Taste Like?
Black cardamom is dried over an open fire, which is what gives it such a powerful smokey aroma. Beneath that are notes of resin and camphor, as well as green cardamom's menthol, slightly minty aromas that provide balance to a funky kick. These intense, heady notes put black cardamom in the "warming" spice category, along with black pepper, cloves, and chiles. It's a major component of the spice blend garam masala, which literally means "warming mixture."
How Do You Use It?
This intensity makes it ideally suited to long-cooked dishes in moist environments, where the spice has plenty of time to release its fat- and water-soluble oils. Like green cardamom, you can remove the seeds and use them whole or ground (for a really intense kick), or grind the whole pod. But I mostly use the pods whole. The flavor is still plenty strong, they're easy to pick out, and it's tough to grind them to a fine powder without getting some unpleasant shards along the way.
Such a strong spice needs strong flavors to stand up to it. I like it best with dried chiles, cumin, and—most importantly—lime juice. The sweet acid cuts down on a lot of black cardamom's medicinal flavors, and I consider it essential. Black cardamom is usually used in concert with several other spices, both to temper it down, and because it does a fantastic job of blending disparate flavors together.