We don’t use crab nearly enough, probably because most cooks are daunted by the idea of dealing single-handedly with the beast. But, unless you have a treasure for a fishmonger, who will only sell the freshest of crabs cooked by himself that morning, it is always best to cook your own if you can. There are various ways to do this. Fishmongers often drown them first in desalinated water. The most humane way to kill them, if you have the knack, is to turn them on their backs and stab them with a long awl in the two nerve centers, the first in a vent behind the tail and the other at a point behind the head. If you are a first-timer, ask your fishmonger to show you how. Throwing the crabs into boiling water is no good, as they tend to shoot their claws, which allows water to ruin the meat. I go for the “bring to a boil in salted water” method, where the crabs just seem to doze off as the water heats. When the water is just simmering, cook for 15 minutes for the first pound and 10 minutes for any subsequent same weights.