Thaw crab legs if frozen
Fill a large pot with 1 to 2 inches of water
Add a steamer basket or rack
Bring the water to a boil
Place crab legs in the steamer basket
Cover the pot with a tight-fitting lid
Steam until heated through, about 5 to 7 minutes for thawed legs or 8 to 10 minutes for frozen legs
Remove the crab legs carefully
Serve immediately with melted butter or lemon if desired