Step 1

Preheat an oven to 190°C/gas mark 5 and butter the inside of your ramekins well

Step 2

Place the milk, onion and nutmeg in a pan and bring to the boil, then take off the heat and set aside

Step 3

In a separate pan, melt the butter and stir in the flour and mustard powder

Step 4

Remove the onion from the milk, then bring the milk back to just below boiling

Step 5

Slowly pour the milk into the pan with the flour mixture (over a low heat) whilst continuously beating with a wooden spoon to avoid lumps

Step 6

Remove from the heat and beat in the grated Gruyère and egg yolks, until the mixture is smooth. Season with a pinch of salt and pepper

Step 7

In a clean bowl, whisk the egg whites to soft peaks, then very carefully fold into the cheese mixture, making sure you don't knock the air out

Step 8

Fill the ramekins with the mixture until three-quarters full, then place them in a large roasting tin. Pour boiling water into the tin until it reaches halfway up the side of the ramekins, then place the tin in the oven for 20 minutes. Once the soufflés are well-risen, remove from the oven and allow to cool and sink

Step 9

Turn the soufflés out upside-down onto a buttered baking tray. At this point you can store the soufflés in the fridge for up to 2 days, or freeze. However, be sure to bring them back to room temperature, or defrost completely before the second cooking

Step 10

When you are ready to serve, preheat the oven to 200°C/gas mark 6

Step 11

Sprinkle the soufflés with the extra grated Gruyère cheese, pour over the cream and bake again for about 15 minutes until the soufflés are once again well risen and light golden in colour

Step 12

Serve the soufflés immediately with a selection of dressed salad leaves and, if desired, some of the cream sauce remaining in the pan