Cumin seeds cook extremely well with onions if you're grilling them. The smell is gorgeous and they're good for your gut. Cardamon is if you're making something like a curry, best put in later on in the cooking just before adding sauce (again, grilling) so that the seed remains mostly intact but the perfume is expelled, then once it's finished you fish around for the cardamon seed and take it out because you don't want to eat it.