French Onion Mac and Cheese Casserole Recipe

Name: This French Onion Mac and Cheese Combines Two Favorite Comfort Foods
Prep time: 50 min
Cook time: 85 min
Total time: 145 min
Yield: 12
Ingredients: 6 tablespoons unsalted butter, divided, plus more for greasing the dish; 1 teaspoon kosher salt, plus more for cooking the pasta; 1 pound large ridged elbow macaroni; 2 large sweet onions, thinly sliced lengthwise; 1/3 cup dry sherry; 1/4 cup all-purpose flour; 5 cups whole milk; 1 tablespoon roasted beef bouillon base (such as Better Than Bouillon), optional; 1 1/2 teaspoons garlic powder; 1 1/2 teaspoons onion powder; 1 1/2 teaspoons ground mustard; 1/2 teaspoon freshly ground black pepper; 14 ounces Gruyère cheese, shredded (about 3 1/2 cups), divided; 8 ounces white American cheese, shredded (about 2 cups); Fresh thyme leaves, optional

Gruyère cheese and caramelized onions bring French onion soup flavor to everyone’s favorite comfort food.
Creamy, gooey sauce comes from a blend of Gruyère and easy-melting American cheese.
The addition of beef bouillon intensifies the savory notes for true French onion richness.

My daughter tried French onion soup for the first time a few weeks ago, and despite being a dedicated cheese lover, she didn’t have positive things to report. “All the cheese is on top, and then there’s soggy bread, and under that nothing but stringy onions.”

It’s not the taste she objects to; it’s the format. I know she’ll love this French onion macaroni and cheese casserole, which transposes the flavors of French onion soup to America’s favorite comfort food (as well as her own). It’s cheesy, gooey, and infused with the sweetness of jammy caramelized onions. Make it for a memorable dinner and keep it in your back pocket when you need an impressive make-ahead casserole.

The Best Combination of Cheeses

French onion soup gets its signature cheesiness from Gruyère, an especially nutty type of Swiss cheese.You can find it with the specialty cheeses. This macaroni and cheese won’t be the same without it.

For creaminess, add a little white American cheese, too. Why American cheese in French onion macaroni and cheese? For years, snobs like me objected to cooking with American cheese, but it’s earned a newfound respect among food science nerds for its ability to work with, ahem, real cheese to make a creamy sauce that won’t break.

Simple Tip!

I can’t always find the white American cheese that this recipe calls for. It’s okay to use yellow—the taste is roughly the same—but the color of the finished casserole will be different.

A baked mac and cheese dish topped with melted cheese partially served using a utensil — Simply Recipes / Photo by Jen Causey / Food Styling by Jennifer Wendorf / Prop Styling by Phoebe Hausser

For the Best Caramelized Onions, Don’t Rush

This is a special occasion “cooking to unwind” recipe in part because it’s a time investment. Making caramelized onions happens over low heat and isn’t quick, but for that unmatchable depth of flavor you can’t rush it. As you tend the pan you can do a little prep: measure ingredients, grate the cheeses.

Adding dry sherry at the end helps deglaze all of the flavorful buildup in the pan. The sherry adds its own inimitable, slightly nutty flavor to help echo the Gruyère.

Tips for Making French Onion Macaroni and Cheese

Ask for a block of white American cheese from the deli so that you can shred it yourself. It’s a lot easier than cutting up a pack of slices.
Shred the cheese yourself; pre-shredded blends are coated in starch and don’t melt as smoothly.
Spiking the sauce with concentrated beef bouillon really pushes this macaroni and cheese into verifiable French Onion territory. It’s worth the investment in a jar, which has plenty of uses (add a dab to soups and stews to create instant beefy intensity).

What Is Bouillon? (And Why Better Than Bouillon Is, Well, Better!)

French Onion Mac and Cheese Casserole

Prep Time 50 mins

Cook Time 85 mins

Cooling Time 10 mins

Total Time 2 hrs 25 mins

Servings 8 to 12 servings

This recipe was developed by Marianne Williams. If you prefer not to cook with alcohol, you can substitute the sherry with 1/3 cup beef broth and 2 tablespoons apple cider vinegar.

Keep Screen Awake

6 tablespoons unsalted butter, divided, plus more for greasing the dish
1 teaspoon kosher salt, plus more for cooking the pasta
1 pound large ridged elbow macaroni
2 large sweet onions, thinly sliced lengthwise
1/3 cup dry sherry
1/4 cup all-purpose flour
5 cups whole milk
1 tablespoon roasted beef bouillon base (such as Better Than Bouillon), optional
1 1/2 teaspoons garlic powder
1 1/2 teaspoons onion powder
1 1/2 teaspoons ground mustard
1/2 teaspoon freshly ground black pepper
14 ounces Gruyère cheese, shredded (about 3 1/2 cups), divided
8 ounces white American cheese, shredded (about 2 cups)
Fresh thyme leaves, optional

Prep the baking dish:

Butter a 9x13-inch baking dish and set aside.
Cook the pasta:

Bring a large pot of salted water to a boil and cook the pasta until just shy of al dente, about 1 minute less than cooking time indicated on package. Drain and set aside.
Meanwhile, caramelize the onions:

While the pasta is cooking, melt 2 tablespoons of the butter in a large Dutch oven over medium-low heat. Add the onions and 1 teaspoon salt and cook, stirring occasionally, until the onions are very soft and deeply browned, 30 to 35 minutes.

Add the sherry (or beef broth and apple cider vinegar) and cook, stirring constantly, until completely evaporated, about 1 minute. Transfer the onions to a small bowl and set aside. Rinse the Dutch oven and wipe dry.

Simple Tip!

You can make the caramelized onions ahead of time and store them in an airtight container in the fridge for up to 3 days.
Preheat the oven to 400°F.
Make the cheese sauce:

Return the Dutch oven to medium heat and melt the remaining 4 tablespoons butter; add the flour and cook, whisking constantly, until it no longer smells raw, 1 to 2 minutes. Whisking constantly, add the milk in a thin, steady stream. Bring to a simmer over medium and cook, whisking often, until sauce has thickened and coats the back of a spoon, about 15 minutes.

Whisk in the bouillon, if using, garlic powder, onion powder, ground mustard, and pepper. (If not using bouillon, stir in 1 1/2 teaspoons of kosher salt.) Remove from the heat and whisk in 2 1/2 cups of the shredded Gruyère plus all of the American cheese until smooth. Add 1 1/2 cups of the caramelized onions and the cooked pasta and stir until well combined.
Assemble and bake:

Pour the pasta into prepared baking dish. Top evenly with the remaining caramelized onions and Gruyère. Cover with foil and bake until the cheese has melted and sauce is bubbling around edges, about 25 minutes.

Remove the foil. Turn the oven to broil. Keeping the casserole on the same rack, broil until the cheese has browned, 3 to 5 minutes.
Rest and serve:

Let the casserole rest for 10 minutes before serving. Garnish with thyme, if desired, and serve.

Refrigerate leftovers in an airtight container for 3 to 5 days.

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Nutrition Facts (per serving)
396	Calories
25g	Fat
26g	Carbs
17g	Protein

Nutrition Facts
Servings: 8 to 12
Amount per serving
Calories	396
% Daily Value*
Total Fat 25g	32%
Saturated Fat 14g	72%
Cholesterol 73mg	24%
Sodium 637mg	28%
Total Carbohydrate 26g	9%
Dietary Fiber 1g	5%
Total Sugars 9g
Protein 17g
Vitamin C 2mg	11%
Calcium 623mg	48%
Iron 1mg	6%
Potassium 306mg	7%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.