Turbot Grand Duc — Poached Turbot with Asparagus, Truffle and Mornay Glaze

⏱ 75 min · Serves 4

A true grande cuisine classic, restored: pearly turbot fillets gently poached in their own fumet, crowned with buttered asparagus tips and a few slivers of truffle, then blanketed in a silky Gruyère Mornay and flashed under the grill until blistered and golden. Elegant, old-school, and utterly worth the effort.

Per serving: 598 kcal · 45.0g protein · 16.0g carbs · 38.0g fat

Ingredients

• 4 turbot fillets, skinless, about 160g each
• 400g turbot bones and trimmings (ask your fishmonger)
• 1 shallot, sliced
• 1 small leek, white part only, sliced
• 150ml dry white wine
• 1 bay leaf, few parsley stalks, 6 white peppercorns
• 500ml water
• 16 asparagus spears, woody ends snapped off
• 30g butter, for the asparagus
• 1 small black truffle or 1 tsp truffle paste (optional but traditional)
• 40g butter, for the sauce
• 40g plain flour
• 300ml whole milk, warmed
• 60g Gruyère, finely grated
• 20g Parmesan, finely grated
• 2 egg yolks
• 3 tbsp double cream
• Pinch of freshly grated nutmeg
• Squeeze of lemon juice
• Fine sea salt and white pepper

Method

1. Make the fumet: put the turbot bones, shallot, leek, wine, herbs, peppercorns and water in a wide pan. Bring slowly to a simmer, skim, and cook gently for 20 minutes. Strain through a fine sieve; you want about 500ml. Return 350ml to a shallow pan and reduce the remaining 150ml hard to about 3 tbsp of glaze.
2. Trim the asparagus to neat 10cm tips. Boil in well-salted water for 2–3 minutes until just tender, refresh in iced water, drain and pat dry.
3. Make the Mornay: melt 40g butter, stir in the flour and cook 2 minutes without colouring. Whisk in the warm milk a little at a time, then the reduced fish glaze. Simmer 5 minutes, stirring, until thick and glossy. Off the heat, beat in the Gruyère, Parmesan, nutmeg, salt and white pepper. Cover with clingfilm touching the surface.
4. Season the turbot lightly. Bring the 350ml fumet to a bare tremble (about 80°C) in a wide pan, slide in the fillets, cover and poach 5–6 minutes until just opaque and yielding. Lift onto a cloth to drain.
5. Reheat the asparagus in the 30g butter with a pinch of salt. Shave the truffle finely.
6. Finish the sauce: whisk the egg yolks with the cream and beat into the warm (not boiling) Mornay. Add a squeeze of lemon; it should coat a spoon richly.
7. Arrange the fillets in a buttered gratin dish. Lay 4 asparagus tips over each, scatter with truffle, then nap generously with the Mornay so the fish is fully coated.
8. Grill 10cm from a hot element for 3–4 minutes until glazed, puffed and blistered brown in patches. Rest 1 minute and serve straight from the dish, with plain steamed potatoes and the rest of the Chablis.