Four Cheese Sauce - cooking recipe

Ingredients

2 1/2 cups milk
1/4 cup butter
1/4 cup white flour
1/2 cup grated gruyere cheese
1/2 cup grated Fontina cheese
1/2 cup grated parmesan cheese
1/2 cup grated provolone cheese (try to get aged)
1 teaspoon Dijon mustard (try coarse grained for a change)
1/4 cup dry sherry or 1/4 cup wine, of your choice
1/8 teaspoon salt, to taste

Preparation

In a small saucepan, heat the milk until steaming, but don't let it boil or form a skin.
While the milk heats, melt the butter in a heavy 2-quart saucepan on low heat.
Add the flour and whisk to form a smooth roux.
Continue to cook and whisk for 3 to 4 minutes to thoroughly cook the flour.
Increase heat to medium, and whisk the hot milk into the roux in a thin, steady stream.
Continue to cook until the sauce is smooth and thickened slightly.
Don't stop whisking, since white sauces can burn in an instant.
Lower the heat, add the cheesed, mustard, and sherry, and whisk until the cheeses melt.
Using a double boiler or a heat diffuser, gently cook on very low heat for about 10 minutes, stirring occasionally.
Add salt to taste.
Enjoy!