A springtime speciality at The Waterside Inn, these soufflés are immensely popular and certainly merit the time taken to prepare them … once tasted, never forgotten.
8 fine langoustines
salt and freshly ground pepper
2 tbsp groundnut oil
4 button mushrooms, sliced
3 shallots, very thinly sliced
2 tarragon sprigs
600ml (2½ cups) ready-made fish stock (bought fresh stock is fine)
50g (3½ tbsp) softened butter, to grease dishes
20g (1½ tbsp) butter
20g (2½ tbsp) plain (all-purpose) flour
pinch of cayenne
4 medium egg yolks
75ml (5 tbsp) double (heavy) cream
1 tbsp Cognac or Armagnac (optional)
8 medium egg whites
Add the langoustines to a pan of boiling salted water and cook for 4 minutes. Drain and shell the langoustines when they are cool enough to handle. Cut the tail meat into 1 cm (½in) pieces, place in a bowl and cover with cling film (plastic wrap). Split the heads lengthways with a heavy knife and use for the stock.
Heat the oil in a saucepan, add the langoustine heads and cook over a medium heat to colour them, stirring every minute. Add the mushrooms, shallots and tarragon, and sweat gently for 5 minutes. Add the fish stock and cook over a medium heat until reduced almost by half. Pass the stock through a chinois, pushing with the back of a ladle to extract as much flavour as you can from the langoustine heads. Put the stock to one side to cool slightly.
Butter the insides of 8 deep 8 cm (3¼in) ramekins, about 6 cm (2½in) high. Melt the butter in a small saucepan, add the flour and cook for 2 minutes, stirring constantly with a whisk, to make a roux. Still stirring, add just 220 ml (scant 1 cup) of the langoustine stock and bring to the boil over a medium heat. Let it bubble gently for a minute or two, then pour into a bowl. Season lightly with salt and a pinch of cayenne, and whisk in the egg yolks. Cover the bowl with cling film (plastic wrap) and leave to cool slightly.
To make the shellfish coulis, put the rest of the langoustine stock into a small saucepan and bring to the boil. Immediately add the cream, and the Cognac if using, and let bubble for 2 minutes, then season with salt and pepper to taste; keep hot.
Preheat the oven to 200ºC/400ºF/Gas 6. Beat the egg whites with a pinch of salt until soft peaks form. Immediately mix one-third into the warm soufflé mixture with a whisk, then, using a large spoon, fold in the rest until evenly incorporated. Half-fill the ramekins with the mixture. Gently warm the langoustine tails and divide them between the dishes, then fill up with soufflé mixture to come 5 mm (¼in) above the rim.
Stand the ramekins in a deep ovenproof dish lined with a sheet of greaseproof paper and pour in enough almost-boiling water to come halfway up the sides. Bake for 6 minutes until well risen and golden.
Take these very light and delicate soufflés to the table straight from the oven. Make a little slit in the middle with a knife tip and pour in the hot langoustine coulis to serve.