Stuffed Baked Mussels

Name: Stuffed Baked Mussels
Ingredients: 2 pounds medium fresh mussels, scrubbed and de-bearded, preferably Green Lipped; 3 tablespoons olive oil, divided; 2 cloves garlic, roughly chopped; 1/4 teaspoon red pepper flakes; 1/2 cup dry white wine, such as Sauvignon Blanc; 3 sprigs fresh thyme; 1 cup finely diced onion; 1 cup finely diced red bell peppers; 1 teaspoon finely minced serrano chile; 1 1/2 cups seeded and finely diced Roma tomatoes (about 4); 2 tablespoons unsalted butter; 3 tablespoons flour; 1/2 cup whole milk, at room temperature; 2 cups panko breadcrumbs, divided; 3 cups rock salt; 1/8 teaspoon nutmeg, freshly grated; 1 teaspoon sea salt; 1 teaspoon fresh cracked black pepper; 2 tablespoons Italian flat-leaf parsley, for garnish; 1 lemon, cut in wedges, for garnish