Classic Mornay Sauce

published Jul 31, 2022
Mornay Sauce Recipe

Mornay sauce seems intimidating, but it’s a shockingly easy and relatively quick cheese sauce to make, and great to have in your cooking repertoire for many dishes.

Makes2 1/4 cups

Prep10 minutes

Cook30 minutes

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A  photo of a white sauce (Mornay sauce - a béchamel sauce with grated cheese added) in a gravy boat with some hard cheese on the side.
Credit: Tara Holland

Mornay sauce may sound fancy, but it’s a surprisingly easy and relatively quick sauce to make. This creamy, cheesy, and totally classic French sauce is a great addition to your recipe artillery because it can be used in so many dishes — whether it’s a gratin, roasted vegetables, or even mac and cheese!

What Is Mornay Sauce?

Mornay sauce is a silky, white cheese sauce typically made with Gruyère (or Swiss cheese), although sometimes Parmesan is in the mix, too. It originates from France and is derived from one of the five French mother sauces. In this case, the mama is béchamel sauce, a simple white sauce made with a blond (pale) roux and milk. This mother sauce is the base of most cheese or creamy sauces, including parsley sauce. To turn béchamel into mornay, shredded white cheese is whisked in. An onion piqué — half a peeled onion that has a bay leaf pinned to it — is also traditionally used when making mornay sauce to enhance the flavor. I like to infuse the milk with it first when it’s warming and again when the sauce is thickening. A pinch of freshly grated nutmeg lends depth while a touch of Dijon mustard adds delightful piquancy.

Credit: Tara Holland

What Does Mornay Sauce Taste Like?

Mornay sauce is like a leveled-up version of cheddar cheese sauce, enhanced by the onion piqué and combination of cheeses. The Gruyère is an excellent melty cheese with a nutty flavor. Although Parmesan is not French, I was taught to make mornay sauce in culinary school using a 50:50 ratio of Gruyère to Parmesan. It adds a punch of flavor and saltiness.

How to Use Mornay Sauce

Mornay sauce is incredibly versatile. It goes particularly well with vegetables, white fish, crab, and shrimp.

  • Pour it over a whole roasted cauliflower.
  • Make mac and cheese.
  • Use it in any vegetable gratin, such as this broccoli and cauliflower gratin.
  • Make a fish pie or cod mornay: Both are very popular in the U.K. The fish is usually poached in milk, drained, tossed in mornay sauce (sometimes with cooked shrimp and spinach), then topped with mashed potatoes and a crispy, cheesy breadcrumb topping. 
  • The sauce is also typically used as a base for a cheese soufflé once egg yolks and beaten egg whites have been folded in. 

Mornay Sauce Recipe

Mornay sauce seems intimidating, but it’s a shockingly easy and relatively quick cheese sauce to make, and great to have in your cooking repertoire for many dishes.

Prep time 10 minutes

Cook time 30 minutes

Makes 2 1/4 cups

Nutritional Info


  • 1/2

    small yellow onion

  • 1

    large dried bay leaf

  • 3

    whole cloves

  • 2 1/4 cups

    whole milk

  • 2 ounces

    Gruyère cheese

  • 2 ounces

    Parmesan cheese

  • 3 tablespoons

    unsalted butter

  • 3 tablespoons

    all-purpose flour

  • 3/4 teaspoon

    kosher salt, plus more as needed

  • 1/8 teaspoon

    ground white pepper

  • 1/8 teaspoon

    freshly grated nutmeg (optional)

  • 2 teaspoons

    Dijon mustard (optional)


  1. Peel 1/2 small onion, carefully trimming around the root end so it is still intact. Place 1 dried bay leaf onto the flat part of the onion and use 3 whole cloves to pin the leaf to the onion, pressing the cloves firmly to secure it. (This is called an onion piqué, used to flavor the sauce.) Place in a small saucepan.

  2. Add 2 1/4 cups whole milk and bring to a gentle simmer over medium heat. Reduce the heat to low and let the milk warm and infuse, stirring occasionally to prevent a skin from forming, for 10 minutes. Meanwhile, grate 2 ounces Gruyère cheese on the large holes of a box grater (about 1/2 cup). Finely grate 2 ounces Parmesan cheese on the smallest holes of the box grater (about 1 cup).

  3. Remove the saucepan from the heat. Pour the milk mixture through a fine-mesh strainer into a liquid measuring cup. Reserve the onion piqué. Transfer 1/4 cup of the milk to a small bowl.

  4. Give the saucepan a good rinse and wipe to remove any milk residue. Melt 3 tablespoons unsalted butter in the cleaned saucepan over medium heat, making sure the butter doesn't brown. Add 3 tablespoons all-purpose flour and cook, whisking continuously, for 2 minutes until foamy, bubbly, and pale yellow.

  5. While whisking constantly, slowly pour in the the remaining 2 cups warmed milk about 1/4 cup at a time. It will initially aggressively bubble and instantly turn into a thick paste, then look like scrambled eggs, and finally become smooth and runny once all of the milk is whisked in.

  6. Return the onion piqué to the saucepan. Reduce the heat to medium low and simmer, gently stirring with a wooden spoon and scraping against the botton and corners of the pan, until pourable but thick enough to coat the back of a spoon, about 5 minutes.

  7. Remove and discard the onion piqué. Vigorously whisk the sauce again until smooth (or strain through a fine-mesh strainer if desired). Add 3/4 teaspoon kosher salt, 1/8 teaspoon ground white pepper, and 1/8 teaspoon freshly grated nutmeg if desired and stir to combine.

  8. Reduce the heat to low. Add the cheeses a handful at a time, whisking after each addition. It will instantly seize up and thicken. To loosen, add the reserved milk a tablespoon at a time as needed until the desired consistency is reached. Add 2 teaspoons Dijon mustard if desired and whisk to combine. Taste and season with more kosher salt as needed. Give the sauce once final whisk until smooth. Serve immediately or press a sheet of plastic wrap directly onto the surface of the sauce to prevent a skin from forming to keep warm.

Recipe Notes

Parmesan cheese substitute: 4 ounces Gruyére, raclette, or Swiss cheese can be used in place of the Parmesan. And although not traditional, you could also substitute it with white cheddar cheese.

Make ahead: Although the sauce is better served immediately, it can be made up to 4 days ahead and refrigerated in an airtight container. Reheat on the stovetop over low heat and whisk until smooth. The sauce will have thickened significantly, so you may need to loosen it with a splash of milk when reheating and adjust the seasoning as needed.