Mornay Sauce - cooking recipe

Ingredients

2 ounces clarified butter
2 ounces bread flour
4 cups milk
1/2 small onion, peeled
1 whole clove
1/2 small bay leaf
salt
nutmeg
white pepper
4 ounces grated gruyere cheese
2 ounces parmesan cheese (freshly grated)
2 ounces raw butter
hot milk or appropriate stock

Preparation

Make a Bechamel sauce as follows: Heat clarified butter in medium size saucepan.
Whisk in bread flour and stir and cook over low heat until light cream color, but at least 1 minute.
Cool slightly.
In another saucepan, scald the milk.
Gradually add milk to the roux (flour and butter mixture) beating constantly with whisk.
Bring sauce to a boil, stirring constantly.
Reduce heat to a simmer.
Stick the bay leaf to the onion with the clove.
Place onion in sauce.
Simmer at least 15 minutes stirring occasionally.
Season very lightly with salt, nutmeg and white pepper.
Strain through a china cap.
Place plastic wrap on sauce to prevent formation of skin.
Cool in cold water bath and store in freezer in ziplock bags for later use, or keep warm over warm water bath for use in dishes being currently prepared.
To 1 qt of the bechamel over low heat add the gruyere and parmesan cheeses, stirring in until just melted.
Remove from heat and gently stir in the 2 oz raw butter.
Thin out with the hot milk or stock appropriate to the dish being served if necessary.