
In a small pot, add the melted butter, followed by the garlic, onions, lemon, and chopped parsley leaves.
Add the mussels, wine, and salt and pepper. Cover the pot and cook over high heat for about five minutes, shaking the pan intermittently until the mussels open.
Slice the bread to medium thickness and rub garlic over each slice. Drizzle with olive oil and lightly toast on both sides.
Serve the mussels directly in the pot, with the bread on the side.