Grains of paradise are becoming easier to find but are still not as widely available as they might be. The best hunting grounds are West Indian or African stores (look for the whole dried pods), or specialist spice shops and mail order companies such as Seasoned Pioneers.
It’s interesting to mix grains of paradise with peppercorns, or with cardamom and fragments of nutmeg, in the same mill; or even have a dedicated mill if you like the flavour.
Grind the grains as you need them, and add an extra sprinkling just before serving; that way you get another whiff of the blissful aroma.