Preheat the oven to 200°C.
Place whole langoustines on foil, drizzle with oil and lemon juice, seal tightly, and bake for 10-15 minutes.
Heat oil in a pan and sauté shallot and garlic until softened.
Add langoustine shells, heads, and tomato purée, cooking for 2 minutes.
Add peppercorns, parsley stalks, lemon zest, and wine, then boil to reduce volume by half.
Add 150ml boiling water and reduce liquid by half again before straining through a sieve into a clean pan.
Stir in double cream, boil until thickened, and season with salt and pepper.
Toss the cooked linguine into the sauce until well coated.
Serve pasta in a bowl topped with the baked langoustines.