Mornay Sauce might be just the sauce you are searching for. This recipe serves 16. One serving contains 91 calories, 4g of protein, and 7g of fat. This recipe covers 3% of your daily requirements of vitamins and minerals. 1 person found this recipe to be flavorful and satisfying. From preparation to the plate, this recipe takes around 45 minutes. Head to the store and pick up milk, onion, butter, and a few other things to make it today.
Place butter in a small saucepan over medium-low heat; cook until butter melts, stirring occasionally.
Add onion to pan; cook 10 minutes or until tender (do not brown), stirring occasionally.
Sprinkle flour over onion; cook 2 minutes, stirring occasionally.
Gradually add milk to flour mixture, stirring with a whisk until smooth; bring to a simmer. Simmer 10 minutes or until thickened, stirring frequently. Strain mixture through a fine sieve over a bowl; discard solids.
Stir in salt, pepper, and nutmeg, if desired.
Wipe pan clean with paper towels. Return sauce to pan, and place over medium-low heat.
Add Gruyre cheese, stirring until smooth.