Fill a big pot with enough water to fully submerge the legs. Add a generous handful of salt—like, generous—and maybe a splash of lemon juice or a bay leaf if you’re feeling fancy. Bring it to a rolling boil.
Drop the frozen legs straight in, cover the pot, and set a timer for 4 to 6 minutes. That’s it. Yes, you read that correctly: minutes, not hours. Overcooking is the number one way to make them tough, so resist the urge to let them party in the water.
When the timer goes off, fish them out with tongs. Run them under cold water just long enough to handle, or let them cool on a plate. Meanwhile, melt your butter, because life is too short for dry crab.
