Filet de Turbot Rôti, Sauce Nantua Royale et Écrasé de Pommes de Terre Truffé

Prepare the Écrasé de Pommes de Terre Truffé: Peel and quarter the potatoes. Place them in a large pot, cover with cold salted water, and bring to a boil. Cook until fork-tender, about 15-20 minutes. Drain thoroughly and return the potatoes to the hot pot over very low heat for 1-2 minutes to evaporate any excess moisture.

Pass the dried potatoes through a ricer or mash them thoroughly with a fork or potato masher until smooth. In a small saucepan, gently warm 80g unsalted butter and 100ml heavy cream. Add this warm mixture to the mashed potatoes along with the black truffle paste. Mix until the potatoes are smooth, creamy, and well combined. Season generously with sea salt and white pepper to taste. Cover and keep warm.

Prepare the Sauce Nantua Royale: If using head-on shrimp, remove the heads and shells and reserve them. Quickly sauté the reserved heads and shells in a teaspoon of olive oil in a small saucepan until they turn pink. Deglaze with a splash of brandy and white wine, then add the fish stock (or water). Simmer for 10 minutes, then strain the liquid, discarding the solids, to create a flavorful shrimp stock. If using pre-peeled shrimp, use fish stock directly.

Melt 10g unsalted butter in a medium saucepan over medium heat. Add the finely minced shallots, diced carrot, and diced celery. Sauté gently until the vegetables are softened, about 5-7 minutes. Add the minced garlic and tomato paste, cooking for another minute until fragrant.

Deglaze the pan with the remaining brandy/Cognac, scraping up any browned bits from the bottom. Allow it to reduce by half. Add the remaining dry white wine and reduce by half again.

In a separate small saucepan, melt the remaining 20g unsalted butter. Whisk in the all-purpose flour to create a roux, cooking for 1 minute. Gradually whisk in the prepared shrimp stock (or fish stock) until the mixture is smooth and slightly thickened. Simmer for 5 minutes.

Pour the roux-thickened stock into the vegetable mixture. Bring to a gentle simmer. Stir in the 200ml heavy cream and a pinch of cayenne pepper. Chop the peeled shrimp into small, bite-sized pieces. Add the chopped shrimp to the sauce and simmer gently for 3-5 minutes, or until the shrimp are cooked through and the sauce has thickened slightly. Do not boil vigorously. Season the sauce with salt and white pepper to taste. Keep warm.

Roast the Turbot Fillets: Preheat your oven to 200°C (400°F). Pat the turbot fillets dry thoroughly with paper towels. Season generously on both sides with sea salt and freshly ground black pepper.

Heat 30g unsalted butter and 1 tablespoon olive oil in an oven-safe, non-stick pan or cast-iron skillet over medium-high heat until the butter is foaming. Carefully place the turbot fillets into the hot pan, presentation-side down. Sear for 2-3 minutes until a beautiful golden-brown crust forms.

Flip the fillets and immediately transfer the pan to the preheated oven. Roast for 6-8 minutes, or until the fish is opaque throughout and flakes easily with a fork. Cooking time may vary slightly depending on the thickness of your fillets.

Assemble and Serve: Spoon a generous portion of the warm Écrasé de Pommes de Terre Truffé onto the center of each serving plate. Carefully place a roasted turbot fillet on top of or alongside the truffled potatoes.

Spoon a generous amount of the warm Sauce Nantua Royale over and around the turbot fillet. Garnish with a sprinkle of finely chopped fresh chives. Serve immediately and enjoy this luxurious French masterpiece.