The best size of crab to buy weighs around 3 lb with the claws attached, usually sold already boiled or sold dressed (ready to eat). The brown meat comes from the shell and the white meat from the claws.
Twist off the claws and legs, close to the body. Open the crab from the back. Get rid of the feathery, spongy-looking grey bits, known as dead man's fingers, and the little sac from behind the head. The rest of the crab is edible. Remove the white meat from the legs, the claws and the body with a fork or a pick, then scoop out all the brown meat. Place the different coloured meats into separate bowls.
To boil a crab wash it in cold water, then plunge it into sufficient boiling : court-bouillon to cover. Allow to simmer for 20 minutes, according to weight, then leave to cool completely in the liquid.