If you like stuffed clams, you'll love this variation. The mussels are steamed open, then topped with garlicky herbed bread crumbs that truly complement the plump bites of briny flavor beneath.
Cooks' notes:
·Bread-crumb topping, without parsley, can be made 3 days ahead and chilled, covered. Stir in parsley before using.
·Mussels can be assembled (but not baked) 4 hours ahead and chilled, covered.