This is a classic French dish in which both main ingredients – pike and crayfish – come from fresh water. Pike has an unusual bone structure.
4 skinned pike fillets, each about 160-180g
Sea salt and freshly ground white pepper
16-20 live crayfish
Olive oil, for frying or roasting
A small knob of butter (optional)
Sauce Nantua (see below)
½tbsp chopped tarragon
Season the pike fillets with salt and pepper and steam for about 10 minutes. If you haven't got a steamer, preheat the oven to 190C/gas mark 5, lay the fillets in a roasting tray with about 2cm of hot water, cover with foil and cook in the oven for 15 minutes. This steaming causes the flesh to shrink a little, leaving the bones protruding so they can be pulled out with a pair of pliers or tweezers. There are lots, so be patient – it's worth it.
Cook the crayfish in simmering, salted water for 5 minutes, then plunge them into cold water. Remove the meat from the shells and the claws if they are big enough. Break the shells up a little with a heavy knife and use to make the sauce Nantua.
Cook the pike fillets again. Either fry them in olive oil for 2-3 minutes on each side, then add a small knob of butter and continue to fry them until lightly browned; or preheat the oven to 200C/gas mark 6, heat a couple of tablespoons of olive oil in a roasting pan and roast them for 10-12 minutes or until lightly coloured.
Meanwhile, if necessary, simmer the sauce until it is coating consistency, stir in the tarragon and drop in the peeled crayfish for a minute to reheat them. To serve, spoon the sauce over the fish fillets.