To make the fish cream sauce: In a medium saucepan, combine the chicken stock, fish stock, mussels, white wine, mushrooms, peppercorns, parsley, and chervil stalk together. Season with salt and pepper. Cook on medium high heat and reduce until about 3/4 of the liquid remains Remove the mussel shells and mussels. Add the cream and reduce further by half. Keep warm.
To make the poached turbot: In a medium pot of boiling water, cook 8-ounces of the fresh peas until almost overcooked. Drain well and season with salt and pepper. Transfer to a food processor and puree.
Cut the iceberg lettuce into fine strips or shreds. Boil the remaining peas and when just cooked, remove with a slotted spoon to a bowl of cold water. In a large skillet, heat 2 tablespoons of the butter on medium-low heat. Add the shallots and garlic and sweat them, about 4 minutes. Then add the whole and pureed peas and iceberg lettuce, cook until lettuce has wilted. Season with salt and pepper, and keep warm.
In a large wide saucepan, combine the wine and chicken stock together. Bring up to a mild simmer on low heat. Add the turbot and lightly poach. When almost cooked, about 8 minutes, add the langoustines and cook for an additional for 2 minutes. Remove the fish and langoustines, and keep warm.
In a medium skillet, heat the remaining 2 tablespoons butter on medium-high heat. Add the giroles and cook until soft. Drain well and set aside.
Combine the reserved fish cream, horseradish cream, cayenne, and lemon juice. Finish with a spoon of whipped cream and using a hand blender, mix well together.
To serve, place a large spoonful of the pea puree in the center of the plate and decorate with 5 pieces of buttered asparagus around the plate. Sprinkle with giroles. Place the turbot on top of the puree and 2 pieces of langoustines on top of the fish. Spoon some of horseradish cream sauce on top and garnish with sliced truffles and parsley.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Chef David Nichols, Mandarin Oriental Hotel - London, England