Tarragon Prawn Fricassée

Peel and devein the prawns, reserving all the shells and heads. Pat the peeled prawns dry with kitchen paper. Mince the shallots and garlic. Pick the tarragon leaves from the stems, keeping the leaves and stems separate. Measure out all remaining ingredients.

Heat 1 tbsp butter and the olive oil in a wide saucepan over high heat until the butter foams and the foam subsides. Add the reserved shells and heads and cook, stirring frequently, until they turn deep orange and smell toasty, about 4–5 minutes.

Add the tomato paste to the shells and stir constantly for 1 minute until it darkens slightly and coats the shells.

Pour in the white wine and tarragon stems, scraping up any browned bits. Simmer over medium heat until reduced by half, about 6 minutes. Strain through a fine-mesh sieve, pressing the shells firmly to extract all the liquid; discard the solids. You should have roughly 100 ml of prawn bisque.

Wipe out the pan and melt 1 tbsp butter over medium-low heat. Add the shallots with a pinch of salt and sweat, stirring occasionally, until completely softened and translucent but not coloured, about 6 minutes.

Add the garlic and stir for 1 minute until fragrant.

Pour in the vermouth and increase the heat to medium-high. Simmer until reduced by two-thirds and the sharp alcohol smell has mellowed, about 4 minutes.

Pour in the reserved prawn bisque and the double cream. Stir in the Dijon mustard and cayenne. Simmer over medium heat, stirring occasionally, until the sauce coats the back of a spoon, about 5 minutes.

Season the prawns with the remaining salt and white pepper. Push the sauce to the edges of the pan, add the remaining 1 tbsp butter to the centre, and lay the prawns in a single layer. Cook over medium heat until the prawns are pink and opaque on the underside, about 2 minutes. Use a meat thermometer to confirm the prawns have reached an internal temperature of 63°C.

Turn the prawns, stir gently into the sauce, and cook for a further 1 minute until just cooked through at 63°C throughout. Remove from the heat immediately to prevent overcooking.

Stir in the lemon juice, lemon zest, and three-quarters of the tarragon leaves. Taste and adjust the seasoning. Serve immediately in warm shallow bowls, scattered with the remaining tarragon leaves. Accompany with crusty bread or steamed rice.