Baked Stuffed Fish Fillet

Name: Baked Stuffed Fish Fillet
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Cuisine: American
Ingredients: 1 1/2 to 2 pounds thin fish fillets, such as flounder, sole, or tilapia; 1 teaspoon kosher salt, plus more to taste; 3 tablespoons finely chopped onion; 1/2 cup finely chopped celery; 6 tablespoons butter , melted; 1/8 teaspoon freshly ground black pepper; 1 teaspoon dried sage, crumbled; 4 cups dry bread, cut or torn into 1/4-inch pieces; 6 teaspoons butter; Chopped parsley , for garnish; Lemon wedges, optional