Try this recipe served over a bed of Polenta

Melt butter, gently sauté shallots, pancetta and mushrooms for 5 minutes. Add flour, cook for 1 minute. Slowly add stock, then milk, then herbes. Simmer for 4-5 minutes.

Brush fish with oil, grill for 4-5 minutes on each side until cooked through. Rest the fish on a bed of starch (polenta, mashed potatoes, orzo, etc.) then pour on the sauce just before serving. Garnish with parsley.