8: Stir to mix well, then leave to simmer on low heat for 40 minutes.
9: After this, strain the contents of the saucepan through a sieve and discard everything in the sieve.
10: You will now have a very flavoursome langoustine stock. Note: this stage of the recipe can be prepared in advance and the stock kept in a sealed jar in the fridge or in the freezer.
11: Prepare the sauce: Pour the stock into a small saucepan on low heat and reduce by half. There should only be 4 or 5 tablespoonsful of liquid left.
12: Then add 200 ml liquid cream, mix well, turn the heat up slightly and bring to the boil. Add 1 knob butter and leave to reduce on low heat again until thickened. Check the seasoning and your sauce is ready.
13: Prepare the sole turbans: Bring a saucepan of salted water to the boil. You can add a richer flavour to the dish by using fish stock, as in the photo, but this is not essential.
14: Salt the sole fillets on both sides.
15: Role into a hollow tube, like in the photo, and fix with two toothpicks so that they do not unroll during cooking.
18: ...then drain on a wire rack. Remove the toothpicks as this is easier while the fillets are still really hot.
19: Pour 1 tablespoon olive oil into a frying pan on medium heat. When hot, sauté the langoustines until nicely browned. Heat the serving plates, particularly important for this recipe.
20: Assemble the turbans: Arrange 2 turbans on each plate.
21: Fill with sautéed langoustines and pour the sauce over or around. Garnish with, for example, a cherry tomato and a parsley leaf. Serve immediately.
Remarks
The main difficulty in this recipe is having everything ready at the same time: the sauce, sole turbans and langoustines all need to be hot. The trick - and key to success for this dish - is to make the langoustine stock the day before, even several days earlier. It is also important to assemble the turbans on hot plates.