Start by cleaning the Mussels: discard any with cracked shells, pull off beards, and rinse well under cold water. Leave the mussels in a bowl of cold water for 10–15 minutes to expel grit, then drain and set aside.
Finely mince the Shallots and the Garlic Cloves. Roughly chop the leaves from the Thyme Sprigs if you prefer smaller pieces (you can leave them whole and remove later if you like).
In a large, heavy pot or deep skillet, melt about 2 tablespoons of Unsalted Butter over medium heat. Add the shallots and garlic and cook gently until translucent and fragrant, about 2–3 minutes—do not let them brown.
Pour in the Dry White Wine and add the Bay Leaves. Increase the heat to medium‑high and let the liquid come to a simmer for 1–2 minutes to cook off some alcohol and concentrate the flavors.
Add the cleaned Mussels to the pot, give everything a quick toss to coat, then cover with a tight lid. Steam the mussels for 5–7 minutes, shaking the pot once or twice, until the shells have opened.
Carefully remove the lid; use a slotted spoon to transfer opened mussels to a warmed serving bowl. Discard any mussels that remain closed after cooking.
Turn the heat back under the pot and let the cooking liquid reduce slightly for 2–3 minutes. Swirl in an additional knob of butter to enrich the sauce, then season with freshly ground Black Pepper to taste.
Scatter chopped Flat-Leaf Parsley over the mussels and give everything a gentle toss or spoon the sauce over the top to coat.
Slice the Baguette and toast or grill the slices until golden. Serve the mussels hot with the crusty bread alongside for dipping into the garlicky wine‑butter broth.
