FENNEL SEED. Although occasionally in some locations, you’ll be able to locate ground fennel seed, in most instances you’ll have to grind it yourself.
Do this with a mortar and pestle.
Or, place seeds in a plastic bag and pound with a hammer till pulverized. Remove from bag and roll with a rolling-pin, repeatedly, using hard pressure till powder-like.
A coffee grinder also works well. Crush dried rosemary leaves the same way.