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.

Clarify 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.

Stiffen 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.