Prepare all the ingredients.
Bring the milk to a boiling point.
Melt the butter in a pot.
Add the flour in one shot and stir to combine well.
Cook the white roux for 2 to 3 minutes over low heat. Beware not to burn it.
Let it cool. You just made a white roux.
Away from the heat, pour the boiling milk on the cold white roux.
Whisk to combine thoroughly...
And cook over medium heat for 4 to 5 minutes. You will get what is called a bechamel sauce.
the eggs. Keep the whites refrigerated.
Add the egg yolks...
...and cook for an additional 2 to 3 minutes.
Put the sauce in a bowl and leave to cool. Add the grated cheese. This is a Mornay sauce.
Whisk the egg whites with a pinch of salt until stiff.
the whites...
..who must be really stiff.
Combine a bit of the whites with the mixture with a wisk. It allows the Mornay sauce to be more fluid.
Combine gently the remaining egg whites with a wooden spatula, stirring in a circular pattern.
This mixture must be used immediately.
Butter and flour 6 soufflé pans or large ramequins.
Fill up each pan up to 3/4.
Transfer to a warm oven (200°C or 392°F)
Bake for 15 to 20 minutes. The soufflés rise and turn golden.
Serve immediately. A soufflé cannot wait. You must serve them as soon as you take them out of the oven, or they'll collapse.