Twice-baked butternut squash and sage soufflé

Method

1. Heat the oven to 220°C/200°C fan/gas 7. Put the squash and garlic in a large roasting tin, season, then drizzle with a generous glug of oil and toss everything together. Roast for 30 minutes or until tender.
2. Meanwhile, pour the milk into a saucepan, then add the onion, bay leaf and nutmeg and bring to the boil. Turn off the heat, leave the mixture to infuse for 10 minutes, then discard the onion and bay leaf.
3. In another pan, melt the butter over a low heat. Stir in the flour and mustard powder, then cook until the mixture is bubbling and smells biscuity. Slowly pour in the infused milk, whisking with a balloon whisk as you go, to make a smooth sauce. Cook for 4-5 minutes on a low heat, whisking constantly, until you have a very thick sauce – it should cling to the whisk. Season, then add three quarters of the cheddar and all of the sage and egg yolks. Beat with a wooden spoon until the sauce comes away cleanly from the side of the pan.
4. When the squash is cooked, tip it into a mixing bowl and squeeze in the garlic flesh (discard the skins). Mash until really smooth, then stir into the cheese sauce with a wooden spoon until combined.
5. In a clean, large mixing bowl, beat the egg whites using an electric mixer until medium-stiff peaks form. Fold one spoonful of the egg whites into the sauce to loosen it a little, using a metal spoon. Add the rest, folding it in quickly but gently.
6. Turn the oven down to 180°C/160°C fan/gas 4. Spoon the mix into the prepared moulds or ramekins, filling to the top. Put them in a deep roasting tin, then pour freshly boiled water into the tin to come halfway up the sides of the moulds/ramekins. Bake for 17-18 minutes.
7. When the soufflés have risen and are still a little wobbly in the centre, remove the tin from the oven, then lift the moulds/ramekins out of the water and set aside to cool (they’ll sink a little). Once cool, run the blade of a small, sharp knife around the edge of each soufflé and turn out into individual ovenproof dishes or one large one.
8. Turn the oven to 220°C/200°C fan/gas 7. Pour the cream over and around the soufflés in their dishes/dish, then top with the parmesan and remaining cheddar. Bake for 10 minutes or until golden and bubbling. Serve warm with a sharp green salad.