Cheese and chive soufflé

Heat the milk, onion, carrot, peppercorns and bay leaves in a saucepan over a medium heat.
When milk begins to boil, remove it from the heat, cover and set aside to infuse for 30 minutes, then strain.
Meanwhile, brush the inside of a 1,5 litre soufflé dish with melted butter.
Put grated Parmesan and breadcrumbs into the dish and shake to coat the sides and bottom of the dish. Tip out excess.
Heat 25 ml butter in a saucepan and stir in the flour.
Cook over a medium heat for one minute.
Add the milk slowly, stirring well to prevent lumps.
Stir over medium heat until the sauce thickens.
Remove from the heat and allow to cool for 10 minutes, then beat in the egg yolks one by one, followed by the mustard.
Mix the Gruyère and Cheddar and add three-quarters to the sauce.
Add the chives and season to taste with salt.
Beat egg whites with an electric beater until soft peaks form.
Spoon one spoonful of egg whites into the sauce and stir well, then pour the sauce over the beaten egg whites and fold in gently, using a large metal spoon. Don?t overmix.
Pour carefully into the prepared soufflé dish.
The mixture should be three-quarters of the way up the side of the dish.
Sprinkle over remaining cheese.
Run the blunt side of a knife around the edge of the mixture.
Bake in a preheated 180 °C oven for about 30 minutes until golden, well risen and firm to the touch.
Remove from the oven and serve immediately.