Smoked haddock and gruyère soufflés

Method

1. Heat the oven to 200°C fan/gas 7. Butter the ramekins very well and dust them generously with the parmesan, tapping gently to remove any excess. Put them in a large roasting tin.
2. Put the milk, bay leaf and smoked haddock in a saucepan. Cover and bring to a bare simmer, remove from the heat, then leave the haddock to poach with the lid on for 10 minutes. Remove the fish from the pan – don’t get rid of the milk – and break it into small flakes, discarding the skin and bones.
3. Put the spinach in the pan with the infused milk. Bring to the boil and remove from the heat. Melt the 50g butter in a saucepan over a medium heat. Stir in the flour and cook, stirring, for a minute. Pour in the infused milk and spinach, stirring all the time, then simmer until the sauce has thickened (about 4 minutes).
4. Remove the sauce from the heat and stir in half the gruyère until melted. Beat in the egg yolks one at a time, then gently fold in the haddock (see Know-how). Stir in the mustard, some grated nutmeg and black pepper. Taste and add more nutmeg and pepper if it needs it, and perhaps some salt – depending on how salty the haddock is, it may not need it.
5. In a scrupulously clean bowl, whisk the egg whites until they form stiff peaks but are not dry. Add about a quarter of the egg whites to the spinach and haddock mixture and stir in well to lighten the mixture. Gently fold in the rest with a rubber spatula, drawing the mixture up from the bottom of the bowl and gently folding over until it’s combined.
6. Spoon the mixture into the prepared ramekins so each is two thirds full. Carefully pour boiling water into the roasting tin until it comes halfway up the ramekins’ sides. Cook the soufflés in the oven for 20-22 minutes until puffed up and golden.
7. Remove the tin from the oven and leave the ramekins in the water to cool. Run a spatula around each ramekin and turn the soufflés out. When cold, tightly wrap and chill for up to a day – or freeze (see Make Ahead).
8. To serve, heat the oven to 220°C fan/gas 9. Butter an oven dish large enough to hold the soufflés without touching. Sprinkle half the remaining gruyère in the bottom and arrange the soufflés on top. Pour in the cream, then sprinkle with the rest of the cheese. Bake for 15-20 minutes until golden. Serve immediately