There are many ways to dispatch a live crab but the most humane way of handling this is to put the crab in the freezer for about 2 hours to make it lose consciousness. You can then prepare and cut up the crab following steps 3–5, or as directed in the recipe.
If a boiled crab is needed, prepare the crab following step 1, then drop it into a large saucepan of boiling, salted water and simmer for 15 minutes per 500 g (1 lb 2 oz), or until bright orange all over. Drain and leave to cool. If you are sautéeing crab, prepare it in the same way but cook for 2 minutes, then drain, cool under running water and cut into pieces (see below). Use as directed in the recipe.