Mornay sauce is simply a béchamel sauce with grated Swiss cheese blended in, believed to have been named after Phillippe de Mornay, a 15th century French diplomat. A more elaborate version appears elsewhere in these pages, † as does its mother sauce.† Nevertheless, the classic version often comes in handy, so it is given here.
1½ tbsp <butter>
1½ tbsp Wondra® flour
1 cup nonfat milk
1/8 teaspoon white pepper
pinch freshly grated nutmeg
2 ounces Swiss cheese, grated
In a 1 quart saucepan melt the <butter> over medium-high heat. Add the flour and cook, stirring constantly, until the roux is a pale yellow, about 1 minute. Do not allow it to brown.
Slowly whisk in the milk and continue to whisk until the sauce thickens and reaches the boiling point, about 2 to 3 minutes. Reduce the heat to a simmer, continue to whisk, and season pepper and nutmeg. Simmer for another 2 to 3 minutes to cook away the floury taste.
Stir in the cheese and whisk vigorously until melted. If the sauce seems too thick, thin with a little milk.