• 2 pounds (about 24) mussels
• ½ cup dry white wine or water
• 1 teaspoon thyme
• 2 tablespoons olive oil
• 1 large onion, chopped
• 12 mushrooms, chopped
• 1 teaspoon freshly grated nutmeg
• 2 tablespoons chopped parsley
• salt
• freshly ground black pepper
• 1 10-ounce box frozen spinach, cooked, drained, and chopped
• 2 tablespoons bread crumbs (preferably homemade)
• lemon juice

Scrub the mussels and remove the beards. Soak them in cold water for 10 minutes, then discard all those that are opened or too heavy. Place the mussels in a large pan with the wine or water and thyme. Cover and cook for 5 minutes, or until the shells have opened. Cool.

Preheat oven to 375°.

Discard half of the shell of each mussel. Heat 1 tablespoon of the oil in a heavy-bottomed pan. Add the onion and mushrooms. Cook for 5 minutes, add the nutmeg, parsley, and salt and pepper, and cook for 5 more minutes. Check to see if the seasoning is right. Add the spinach and remove from heat.

If the mussels are unusually large, cut them into two or three pieces with kitchen shears. Put a mussel or a piece of mussel in each shell and spoon the spinach stuffing over it, then smooth the top with your fingers. Sprinkle bread crumbs and a little olive oil on each. Arrange the stuffed mussel shells on a large baking dish with ½ cup of water at the bottom (to prevent sticking), and bake for 15 minutes. Sprinkle with lemon juice just before serving.