The Ligurian word for cozze also means 'muscles' in Italian, so be sure you only ask for them in the vicinity of the Italian Riviera or who knows what you'll get!
The classic recipe is muscoli ripieni alla spezzina—stuffed mussels La Spezia style, a hearty dish that involves making a sauce with mussels, white wine and tomatoes, then laboriously opening and stuffing raw mussels with finely chopped parsley, parmesan, garlic, mortadella, and bound together with egg, and cooking them in the sauce; the latter is delicious with trenette.
Image by cucinagenovese