Sole au Vin Blanc Sole with Mushrooms and Shellfish

Name: Sole au Vin Blanc (Sole with Mushrooms and Shellfish)
Ingredients: 8 tbsp. unsalted butter; 3 tbsp. bread crumbs; 1 tbsp. minced parsley; 2 (6-oz.) skinless fillets Dover or grey sole; Kosher salt and freshly ground black pepper, to taste; 4 oz. white button mushrooms, sliced; 1⁄4 cup dry white wine; 6 oz. small shrimp, peeled and deveined, tails removed; 8 cockles or littleneck clams, scrubbed; 8 mussels, scrubbed