Butter the moulds with melted butter making upward motions with your brush so it helps the soufflé go up. Keep in the fridge until needed.
Melt the butter from the recipe and add the flour. Let boil for 1 minute while stirring with a whisk.
Add the milk little by little of the heat and whisk it so no lumps form.
Put back onto the heat and let boil for a minute so you know you've reached its maximum thickness. Taste to make sure it doesn't taste like flour anymore. If it does, let it boil some more, always stirring.
Add the grated cheese and let it melt. Correct salt level.
Add 2 egg yolks and whisk rapidly.
Transfer mix to another bowl, mixing every so often so a skin doesn't form.
Use a stand or hand mixer to whip up the egg whites.
Add the egg yolks to the mix and then half the egg whites. Mix roughly.
Fold in the other half of the egg whites to preserve as much air as possible.
Fill your ramekins or large mould until about 0.5cm from the top or to the inner rim.
Take to a preheated oven at 180C for 10-15min or until fully risen and golden. If it's a large mould it could take an extra 10min.
Serve IMMEDIATELY because it starts to deflate from the moment it comes out of the oven.