French Onion Mac and Cheese

from 19 votes

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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Main Course

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.
Author: Kelly Senyei
5 from 19 votes
A pot of mac and cheese with caramelized onions and small bowls surrounding it
Prep Time 25 minutes
Cook Time 45 minutes
Total Time 1 hour 10 minutes
Servings 8 servings


  • 10 Tablespoons unsalted butter, divided
  • 2 small yellow onions, thinly sliced
  • 2 cloves garlic, minced
  • 2 teaspoons fresh thyme leaves, minced
  • 1 bay leaf
  • 1/4 cup dry sherry or white wine
  • 2 teaspoons beef bouillon paste
  • 2 teaspoons Worcestershire sauce
  • 1 pound uncooked pasta shells
  • 4 cups whole milk
  • 1/2 cup all-purpose flour
  • 2 cups shredded sharp cheddar cheese
  • 3 cups 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.
  • ★ Did you make this recipe? Don't forget to give it a star rating below!


Calories: 699kcal, Carbohydrates: 59g, Protein: 29g, Fat: 38g, Saturated Fat: 23g, Cholesterol: 113mg, Sodium: 641mg, Potassium: 413mg, Fiber: 3g, Sugar: 10g, Vitamin A: 1226IU, Vitamin C: 3mg, Calcium: 581mg, Iron: 2mg


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Recipe by Kelly Senyei of Just a Taste. Please do not reprint this recipe without my permission. If you'd like to feature this recipe on your site, please rewrite the method of preparation and link to this post as the original source.

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  1. 5 stars
    SOOOO good!! Made it all according to directions and it came out incredible! I thought the cheese might be a little overwhelming but its thankfully not, it has a more subtle flavor but plenty of the good cheese stretch. I loved having it with a baguette to get all the extra cheese sauce with! Thank you for sharing the recipe!

  2. 5 stars
    OMG! This is ridiculously good! Only issue was that the sauce, made to directions, was way to thick and required addition of a fair bit of 2% milk to get a good consistency. Next time I may try adding some sliced, sautéed mushrooms to the onion mixture. Thank you for sharing your terrific recipe.

  3. The cheesy sauce came out grainy. I followed the instructions and went back to check to see if I messed up, couldn’t find out what I did wrong.. any ideas?

    1. Hi Sarah! It sounds like your roux didn’t thicken properly. You can fix the graininess by streaming in additional liquid. Hope that helps!

    2. Sauce was way too thick. Had to fix it. Only half the amount of flour should be needed. Other then that very tasty. If you want a French onion queso dip follow the recipe exactly.

  4. 5 stars
    This was so delicious! The family said it was a keeper. Will be making again soon! Only used one big pot and I just warmed the milk in a large measuring cup in microwave. Made the pasta earlier and it worked out perfectly.

  5. 5 stars
    This was so bomb!! My only complaint is it requires a lot of pans lol especially if you cook up chicken to go with it like we did! Maybe I can premake the sauce next time in the afternoon or bake the chicken to cut down on the pots/pans I need!

  6. 5 stars
    Oh YES!! King of Comfort food it is. I tasted it as soon as it was done and it is a winner. I am also adding buttered toasted Panko bread crumbs on top to bake a little in a 375F oven, along with chicken thighs.

  7. For those wondering about bouillon paste, look for Better than Bouillon in your grocery store soup aisle. Comes in a jar and is worlds better than the cubes.

  8. 5 stars
    French onion soup & mac n cheese. Two of my absolute favorites, so how could they not be better together? Made exactly as written, and will do so many, many more times!

  9. 5 stars
    There’s just two of us so I cut everything in half but the onion part.. that I doubled. I froze 3/4 of the onions after they were done. Next time I want this, the most time consuming part is done!

  10. Hi, this looks yummy! I’m wondering, if I can’t find beef bouillon paste, could I use beef bouillon cubes, and if so, how many?

    1. Hi Linda! I’d use one cube, however the cubes need to be dissolved in water, which will dilute the sauce.