Codfish in Ginger Soy Cream

Name: Codfish in Ginger Soy Cream
Ingredients: 1/2 cup low-sodium soy sauce; 1/2 cup mirin; 1/2 cup water; 2 tablespoons rice wine vinegar; 2 tablespoons light brown sugar; 1 garlic clove, crushed; 1 tablespoon peeled and crushed ginger; 1 teaspoon cornstarch, plus 1 tablespoon water, for slurry; 4 (6-ounce) codfish fillets; Kosher salt and freshly ground black pepper; All-purpose flour, for dusting; Canola oil; 8 large scallions, trimmed; 2 tablespoons chopped ginger; 1 small chile pepper, seeded and chopped; 1/2 cup dry white wine; 1 cup heavy cream; 1 pound mussels; Chervil leaves, for garnish