Tip the milk into a large saucepan with the onion, thyme and a few cracked black peppercorns. Bring to the boil, then turn off the heat, leave to cool and strain into a jug. Melt the butter in a large saucepan. Brush about a third of this all over the inside of a 16cm soufflé dish, then sprinkle over the parmesan to completely coat the dish.

Continue to cook the remaining melted butter over a medium heat until it turns nutty brown. Use a wooden spoon to stir in the flour, mustard powder and cayenne. Cook, stirring, for 1 min until you have a sandy paste, then gradually pour in the milk, mixing it thoroughly before adding more. Once all the milk has been added, cook over a low heat, stirring continuously for 10 mins until thick. Add the yeast extract, if using, and the cheddar, and stir until melted. Season well. Tip into a bowl and set aside to cool.

Heat the oven to 210C/190C fan/gas 7 with a baking sheet inside. Separate the egg whites and yolks, putting the whites into a clean bowl and stirring four of the yolks into the sauce. (You can use the remaining egg yolk in another recipe.) Stir the goat’s cheese into the cooled sauce.

Use an electric or large balloon whisk to beat the egg whites until they just hold their shape. Use a large metal spoon to stir a spoonful of the beaten egg whites into the sauce, then gently fold in the rest, trying to keep as much volume in as you can.

Spoon the mixture into the prepared dish. Run a cutlery knife around the edge to create a ‘top hat’ effect – this ensures the soufflé will rise above the rim without sticking. Put the dish on the hot baking tray in the oven and bake for 25-30 mins until risen with a slight wobble, and the top is deep golden. Serve immediately with a watercress salad, if you like.