If one of these dishes was going to make you a vegetarian, this is it
The poshest thing you can do with a lobster, and the most nerve-wracking. Barely cook the meat, fold it through a silky cognac and mustard sauce, pile it back into the shells and blast it until bubbling and golden. Tread carefully, it's costing you a fortune.
The challenge
- Killing and butchering live lobster
- Béchamel sauce without lumps
- Sauce balance
- Reassembling in shells
French lobster preparation that starts with the uncomfortable task of dispatching and breaking down live lobsters. The meat gets poached just until barely cooked, then mixed into a cognac-spiked béchamel sauce, which needs perfect consistency and bold flavour without overwhelming delicate lobster.
The presentation demands intact, elegant shells filled with creamy, rich filling and properly browned tops, and there's no hiding mistakes when you're serving something this expensive and iconic.
Prep: 45 minutes · Cook: 30 minutes
Ingredients
For the lobster
- 2 live lobsters, about 700 g (1.5 lb) each
- Coarse salt for the cooking water
For the thermidor sauce
- 40 g (3 tbsp) unsalted butter
- 1 shallot, very finely chopped
- 30 ml (2 tbsp) cognac or brandy
- 100 ml (scant ½ cup) dry white wine
- 25 g (3 tbsp) plain (all-purpose) flour
- 300 ml (1¼ cups) whole milk, warmed
- 100 ml (scant ½ cup) double (heavy) cream
- 2 tsp Dijon mustard
- 1 egg yolk
- Pinch cayenne pepper
- 1 tbsp chopped tarragon
- Squeeze of lemon juice
For the topping
- 50 g (½ cup) finely grated Gruyère or Parmesan
- 2 tbsp fine breadcrumbs
- 1 tbsp chopped flat-leaf parsley
Method
- Dispatch humanelyChill the lobsters in the freezer for 30 minutes to sedate them. Place on a board, find the cross-shaped mark behind the head, and push the tip of a heavy, sharp knife straight down through it in one firm motion, then bring the blade down between the eyes. Work quickly and decisively.
- Par-cookBring a large pot of heavily salted water to a rolling boil. Plunge in the lobsters and cook 6 minutes only, then transfer to iced water. The meat should still be slightly translucent in the centre; it finishes cooking in the oven.
- Split and extractTwist off the claws. Lay each body on its back and cut lengthways from head to tail with a large knife to make two halves. Remove the tail meat in one piece, discard the dark intestinal vein and the stomach sac near the head. Crack the claws and knuckles and pull out the meat. Rinse and dry the shells, keeping them intact.
- Chop the meatCut all the meat into 2 cm (¾ in) chunks and keep chilled. Place the empty half-shells on a baking tray, propped up with scrunched foil so they sit level.
- Build the flavour baseMelt the butter in a saucepan over medium-low heat and cook the shallot for 3 minutes until soft but not coloured. Add the cognac and carefully ignite or simply simmer it off, then add the wine and reduce by two-thirds.
- Make a smooth béchamelStir in the flour and cook 1–2 minutes. Take off the heat and add the warm milk a splash at a time, whisking hard after each addition until completely smooth. Return to the heat and simmer, whisking, for 5 minutes until thick enough to coat a spoon. Whisk in the cream and mustard.
- Balance the sauceOff the heat, whisk in the egg yolk, cayenne, tarragon, half the cheese and a squeeze of lemon. Taste: it should be rich and punchy with a mustard kick, but you should still be able to imagine the lobster. Season with salt and white pepper. Fold in the lobster meat gently.
- Fill the shellsHeat the grill (broiler) to high. Spoon the mixture into the half-shells, mounding it slightly. Mix the remaining cheese with the breadcrumbs and scatter over the top.
- Grill until goldenGrill about 10–12 cm (4–5 in) from the heat for 5–7 minutes, until bubbling and browned in spots. Watch it like a hawk. Scatter with parsley and serve right away with lemon wedges.
- Apologise to the lobsterHave a quiet moment of respect for the lobster before you crack in. Then serve with Champagne and enjoy every bite of the richest thing you'll ever eat. If you feel like going vegetarian tomorrow, that's understandable.
Tips from the trenches
- Warm milk plus off-heat whisking is the trick for a lump-free béchamel. If lumps happen anyway, push the sauce through a sieve before adding the cream.
- Under-cook the lobster in the pot. Overcooked lobster turns rubbery, and an expensive rubber dinner is the worst kind.
- If you can't face dispatching live lobsters, buy them freshly cooked from a good fishmonger and skip the par-cooking step.
- Keep the sauce on the thick side; it loosens as it heats in the shells.
“You can only become a chef by mastering your five senses.”— Muriel Barbery
