Inspect mussels to make sure they are tightly closed. Just before cooking, clean wild mussels by scrubbing with a stiff brush and pulling off the beard with a quick tug. Cultivated mussels need only be rinsed in cold water. To remove meat, either steam open or pry shells open and pick out meat.
Steaming
Place 1/4-inch (0.635cm) water (wine and seasoning optional) in the bottom of a large pan, and add mussels. Bring water to a boil, reduce heat, and simmer until shells open (four to five minutes). Throw away mussels that don’t open. Serve mussels in bowls with broth.
Pan-frying
Heat frying pan, then add butter or oil. Add mussel meat and sauté until brown, about two to three minutes.