Step 1

Before starting this Mornay Sauce recipe, make sure you have organised all the necessary ingredients.

Step 2

Bring the milk to a boil.

Step 3

Melt the butter in a saucepan.

Step 4

When the butter starts sizzling, add all the flour at once.

Step 5

Combine well with a whisk.

Step 6

Cook the white roux for a few minutes. Make sure the white sauce does not brown. This is essential to make a successful Béchamel sauce.

Step 7

Pour the boiling milk on the cold white roux.

Step 8

Combine well with a whisk and bring to a boil again.

Step 9

The sauce bechamel should start thickening. Season with salt, pepper and grated nutmeg.

Step 10

Add the egg yolk.

Step 11

Cook for a few minutes, whisking continuously. Add the grated cheese.

Step 12

Transfer the sauce into a recipient and leave to cool. To avoid a crust forming on top, you can tap the surface of the sauce with a knob of butter.