How to Make a Classic Mornay Sauce

Updated: Apr. 05, 2023

Learn how to make this easy mornay sauce—the most delicious cheesy white sauce that can dress up almost any meal.

If you’ve ever sat in the bleachers with a plate of nachos, you know that the chip is just a vessel for the real star of the show: that warm, velvety cheese sauce. Fortunately, nacho cheese, and other cheesy sauces, are not just for stadiums and movie theaters.

Not only can you make mornay sauce at home, but it’s also a lot easier than it sounds. Despite its fancy name, the French sauce comes together easily, and it’s about to take your nacho bar (and roast chicken dinners) up a notch.

What Is Mornay Sauce?

In French cooking, there are five sauces that are considered to be the “mother sauces.” They are the base for all other delicious French sauces. One of those is a bechamel sauce, which combines butter, flour and milk to make a basic thick and creamy sauce. Add some cheese, et voilà! You’ve got your mornay sauce.

The most popular cheese to use is Gruyere, but you can use any semi-firm cheese. Sometimes onions are added if the sauce will be used in something like lasagna but not if you’re aiming for a very smooth final product. And the secret ingredient to it all is a dash of nutmeg.

How to Make Mornay Sauce


  • 2 tablespoons unsalted butter
  • 2 tablespoons all-purpose flour
  • 1 cup whole milk
  • 1/8 teaspoon kosher salt
  • Dash white pepper
  • Dash of fresh grated nutmeg, optional
  • 2 ounces Gruyere cheese, shredded


Mornay SauceTMB Studio

Step 1: Make bechamel

In a small saucepan set to medium heat, melt butter completely and then add the flour. Whisk continuously until it starts to bubble, about one minute. Continue whisking and slowly pour in the milk. It will get very thick at first, but as the milk is added, it will thin out.

Step 2: Season

Reduce heat to low and continue whisking, allowing the sauce to thicken. If there are any lumps, whisk them thoroughly until they’ve smoothed out. Add the salt, pepper and nutmeg.

Step 3: Add cheese

Keeping the heat on low, add cheese a handful at a time, allowing it to almost melt entirely before adding the next bit. Taste for seasoning then remove from heat.

Step 4: Store or serve

Serve immediately. Leftovers can be stored in the fridge with a piece of plastic wrap over the surface to prevent a skin from forming.

Tips for Making Mornay Sauce

  • If you have a lumpy sauce and the whisk just won’t do the trick, you can use a blender or immersion blender to smooth it out entirely.

  • There are so many ways to use a mornay sauce! It can be served over some blanched vegetables like broccoli or asparagus. It can also be used as a sauce in heavier comfort foods like lasagna or poured over the most delicious loaded baked potatoes.

  • Mornay sauce can be stored in the fridge for up to five days, or in the freezer for up to three months. To reheat, warm on low while whisking, adding a splash of milk to thin out as needed.

  • For a variation on the traditional mornay, try adding cheddar cheese in place of the Gruyere for more of a nacho cheese vibe. You can also make it with small diced onions, which would go great in a baked pasta dish or on a burger.