//French Onion Mac and Cheese

French Onion Mac and Cheese

Transform a classic soup into an easy, cheesy entrée with this crowd-friendly recipe for French Onion Mac and Cheese.

A close-up shot of mac and cheese with onions and fresh herbs on top

If ever there was a comfort food to be named King of All Comfort Foods, this pot of cheesy goodness would get my vote … again … and again … and again.

I’ve taken one of my all-time favorite soups and swapped the broth for a luxuriously thick and creamy cheese sauce.

A pot of mac and cheese with caramelized onions and small bowls surrounding it

Something magical happens when cheese sauce and caramelized onions join forces. It’s an unexpected marriage that leads to the perfect balance of savory and sweet flavors. But this wasn’t an easy recipe to perfect.

I’m often asked how many times I’ll attempt a recipe before giving up (Japanese pancakes, looking at you!). I attempted this recipe from a very different approach two other times and neither was worthy of this webpage.

A Dutch oven filled with bechamel cheese sauce and shell pasta

Once I went back to the basics, everything just clicked. Slowly caramelized onions made with fresh thyme and a not-so-secret ingredient (beef bouillon!) guarantee that intense French onion soup flavor. Set those beauties aside while you whip up a silky bechamel sauce starring mozzarella and cheddar cheeses. The melt factor is a 100.

Add in pasta shells (a.k.a. the best noodle for mac and cheese ever) and the result is the ultimate French Onion Mac and Cheese that’s every adult’s dream spin on a childhood favorite.

A pot with mac and cheese surrounded by shredded cheese and fresh thyme

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A pot of mac and cheese with caramelized onions and small bowls surrounding it


French Onion Mac and Cheese

  • 10
    unsalted butter, divided
  • 2
    small yellow onions, thinly sliced
  • 2
    cloves garlic, minced
  • 2
    fresh thyme leaves, minced
  • 1
    bay leaf
  • 1/4
    dry sherry or white wine
  • 2
    beef bouillon paste
  • 2
    Worcestershire sauce
  • 1
    uncooked pasta shells
  • 4
    whole milk
  • 1/2
    all-purpose flour
  • 2
    shredded sharp cheddar cheese
  • 3
    shredded mozzarella cheese

Melt 2 tablespoons butter in a medium saucepan set over low heat. Add the onions, garlic, thyme, and bay leaf and cook until the onions are caramelized, about 35 minutes. 

Increase the heat to high then add the sherry, and cook while scraping up any browned bits, for 1 minute. Add the beef bouillon and Worcestershire sauce and stir to combine. 

Remove the mixture from the heat and discard the bay leaf. Set the mixture aside.

Bing a large pot of salted water to a boil. Add the pasta and cook until al dente, about 10 minutes. Drain the pasta and set it aside.

In a medium saucepan set over medium heat, warm the milk until it is simmering then set it aside.

In a large heavy-bottomed stock pot set over medium heat, melt the remaining 8 tablespoons butter. Once the butter has melted, whisk in the flour and cook, whisking constantly, until it turns light brown in color and has a slightly toasted aroma, about 3 minutes.

Slowly whisk in the warm milk. Continue whisking constantly to avoid any lumps.

Cook the mixture while whisking constantly until it is thick enough to coat the back of a spoon, about 2 minutes.

Reduce the heat to medium. Stir in the cheddar and mozzarella cheeses until they are
melted and the sauce is smooth.

Add the pasta, stirring to combine, then fold in the onion mixture and serve.

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Nutrition Facts

French Onion Mac and Cheese

Amount Per Serving

Calories 699
Calories from Fat 342

% Daily Value*

Fat 38g58%

Saturated Fat 23g144%

Cholesterol 113mg38%

Sodium 641mg28%

Potassium 413mg12%

Carbohydrates 59g20%

Fiber 3g13%

Sugar 10g11%

Protein 29g58%

Vitamin A 1226IU25%

Vitamin C 3mg4%

Calcium 581mg58%

Iron 2mg11%

* Percent Daily Values are based on a 2000 calorie diet.