Turbot in a burnt butter sauce with a sweetheart cabbage salad

This recipe for Turbot in a burnt butter sauce with a sweetheart cabbage salad brings together 2 turbot fillets ( 150–200g/5½–7oz each), skin removed, boneless, 200g/7oz salted butter, cubed, 130g/4½oz unsalted butter, cubed in a practical dish for home cooking. It makes approximately 2 servings.