This decadent French Onion Mac and Cheese recipe infuses all the flavors of your favorite French onion soup in an ultra creamy baked mac and cheese. To make it, thinly sliced onions are cooked until jammy and caramelized before being folded into a luscious béchamel sauce made with a blend of white cheddar and Gruyere. The mac and cheese is finished with a crispy breadcrumb topping before being baked until golden and bubbling.
This is a special occasion side dish that’s perfect for dinner parties, Thanksgiving, Christmas, or anytime you’re craving ridiculously flavorful mac and cheese!
Table of contents
Not-Your-Average Baked Mac and Cheese
I have a classic baked mac and cheese recipe that’s super quick and easy to throw together, has no breadcrumb topping, and is essentially mac and cheese in its purist form.
This insanely creamy French onion version is not that. The recipe I’m sharing with you today is what I’m calling my “Magnum Opus of Mac and Cheese.” It packs in all of the flavors of my favorite French onion soup, delivered in the form of rich and comforting mac and cheese.
I won’t lie, this French onion mac and cheese does require a little extra TLC to prepare than your average stovetop mac and cheese, but the combination of gooey cheddar and Gruyere, sweet caramelized onions, al dente pasta, and crispy breadcrumbs is more than worth the smidgen of extra effort.
This is a special occasion side dish, after all, and on special occasions you’ve got to go all out!
The Key Ingredients
full list of ingredients, quantities & method in the recipe card at the end of the page.
- Pasta. I prefer making my mac and cheese with cavatappi pasta, but any short and sturdy pasta shape will work (think: elbows, mini pene, lumache, etc.).
- Butter + olive oil. I like to use a little of both when caramelizing the onions. The butter adds richness, while the oil raises the smoke point of the butter and keeps it from burning during the long cook time.
- Onions. Yellow onions deliver that classic French onion soup flavor.
- Half and half + heavy cream. This is a Goldilocks situation where using just half and half results in too runny a cheese sauce and using just heavy cream results in too thick a cheese sauce. Use a little of both to achieve the perfect creamy consistency.
- Cheese. Gruyere is the traditional choice when making French onion soup, so it’s a must in this baked mac and cheese recipe! To round out the flavor, I added some white cheddar (which also melts beautifully).
- Dijon. Doesn’t make the cheese sauce taste like mustard, it simply deepens the flavor.
- Herbs and spices. A pinch of ground nutmeg and some fresh thyme are all you need to flavor the sauce. (Plus salt and pepper, of course!)
- Panko breadcrumbs. Are much lighter and crispier than regular breadcrumbs.
Jenny’s Tip: Shred Your Own Cheese, Please!
I know it’s faster to buy a couple bags of pre-shredded cheese to use in this French onion soup mac and cheese, but please buy actual blocks of cheese and shred them yourself.
Pre-shredded cheeses are coated in cellulose or starch to prevent clumping. That coating will make your cheese sauce grainy and it will never become silky smooth and creamy like we want it to.
The easiest way to shred cheese yourself is to bust out the box grater and use the largest holes to shred both cheeses. If you own a food processor, you can also fit it with a shredding disc for quick and easy cheese shredding.
Kitchen Tools I Recommend
The 5 Simple Steps to Making French Onion Mac and Cheese
- Caramelize the onions. This process will take roughly an hour, and there’s no way around it if you want perfectly jammy and sweet caramelized onions. You’re welcome to caramelize the onions up to 2 days ahead of time, if needed.
- Prep the breadcrumb topping. The panko breadcrumbs are tossed with melted butter and crisped up in a skillet over medium heat. Be sure to hit the breadcrumbs with a little fresh thyme, salt, and pepper to add some flavor.
- Cook the pasta until al dente. That’s a fancy way of saying “until it’s mostly done, but has some chewiness to it.” If you cook the pasta all the way at this stage, it will become mushy once tossed with the béchamel sauce and baked.
- Make the cheese sauce. Melt the butter, then sprinkle in the flour and whisk, whisk, whisk until the raw flour flavor cooks out. Stir in the heavy cream, Dijon, and nutmeg before removing from the heat and whisking in the shredded cheese.
Jenny’s Tip: Build the sauce in the same pan you used to caramelize the onions to really pick up that French onion flavor.
- Combine and bake. Fold the cooked pasta and caramelized onions into the cheese sauce, then turn into a buttered 9×13-inch baking dish. Top with the panko breadcrumbs and bake at 425ºF until golden and bubbling.
Serving Suggestions
You can serve this French onion soup mac and cheese as a main or side, depending on the occasion. It’s a decadent addition to any weeknight dinner menu or holiday gathering, and this recipe makes 10 to 12 generous servings.
- Holiday mains. Cheesecloth Turkey, Herb Crusted Beef Tenderloin, Bourbon Glazed Ham, Herb Crusted Prime Rib
- Weeknight mains. Cider Pork Chops, Dutch Oven Roast Chicken, Baked Pork Ribs, Pretzel Crusted Chicken
- Sides. Little Gem Caesar Salad, Grilled Lemon Parmesan Asparagus, Almond Gremolata Green Beans
If you do give this recipe a try, I love hearing about it! Leave a comment with a star rating below. Be sure to subscribe to my weekly newsletter and never miss a new recipe! You can also snap a photo & tag @JENNYGOYCOCHEA on Instagram.
More Homemade Mac and Cheese Recipes
- White Cheddar Mac and Cheese
- Southern Baked Mac and Cheese
- Pumpkin Bacon Mac and Cheese
- Creamy Baked Mac and Cheese
- Stovetop Mac and Cheese
- Bacon Shells and Cheese
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French Onion Mac and Cheese Recipe
Ingredients
Mac and Cheese
- 16 oz short pasta (shells, lumache, elbows, cavatappi, etc)
- 6 tablespoons unsalted butter, divided
- 1 tablespoon olive oil
- 4 yellow onions, thinly sliced (a mandolin is best)
- 1 tablespoon minced fresh thyme leaves
- 3 tablespoons all-purpose flour
- 2 teaspoons dijon mustard
- 3 1/2 cups half and half
- 1/2 cup heavy cream
- 1/4 teaspoon freshly grated nutmeg
- 6 oz white cheddar cheese, shredded by hand*
- 8 oz gruyere cheese, shredded by hand
- kosher salt
- freshly cracked pepper
Thyme Breadcrumb Topping
- 3 tablespoons unsalted butter
- 1 tablespoon chopped thyme leaves
- 2/3 cup panko crumbs
- Kosher salt and pepper
Instructions
- Caramelize the onions. Melt 2 tablespoons of the butter along with the olive oil in a large dutch oven over medium heat. Once the butter is hot and foamy, add the onions and toss well to coat. Cover the pot and let the onions cook for 10 minutes, until they’re starting to wilt. Remove the lid, lower the heat, and add the thyme. Continue to cook the onions, stirring every so often, until they’re deeply caramelized, about 40 minutes. Transfer the onions to a bowl and set aside. This step can be done up to 2 days in advance, but I recommend not washing the dutch oven so that you can use the fond to help build flavor in the sauce.
- Make the panko topping. Melt the butter in a skillet over medium heat and add the thyme. Cook for 1 minute, until fragrant. Add the panko and stir well to coat. Cook for 2-3 minutes, stirring occasionally, until the panko is starting to turn golden brown. Remove from the heat, season with salt and pepper and set aside until ready to use.
- Preheat an oven to 425 F. Lightly grease a 9×13, or 3 quart baking dish with butter. Set aside.
- Bring a large pot of salted water to a boil and cook the pasta to just shy of al dente, usually 2-3 minutes short of the package cooking times. Drain the pasta in a colander and rinse with cool water to stop the cooking process. Let the pasta drain while you make the bechamel.
- Build the sauce. Melt the rest of the butter in the same dutch oven you used to caramelize the onions, scraping up any browned bits from the bottom of the pan. Whisk in the flour and cook for another 2-3 minutes to cook any raw flour flavor out. Slowly whisk in the half and half and bring to a gentle simmer until it’s thickened. Stir in the dijon, nutmeg, and heavy cream. Remove the pot from the heat and whisk in the cheese, a bit at a time, until the sauce is smooth and the cheese is completely melted. Season to taste with salt and pepper.
- Bake. Fold in the caramelized onions and cooked pasta and stir well. Transfer the mac and cheese to the prepared baking dish and top with the panko breadcrumbs. Transfer to the oven and bake for 15-20 minutes, or until the panko is golden brown and the cheese is bubbling. Let the mac and cheese rest for 5 minutes before serving.
Notes
Nutrition
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Rate & Review This Recipe
This recipe was SO WORTH carmelizing onions. I moved a chair in front of the stove for this. The result was perfection. Even the onion-haters and picky eaters went back for seconds. The sauce was perfectly smooth, the breadcrumbs crisp and herby, the pasta had the perfect bite, and the jammy onions gave it a hint of sweetness. We shredded the cheese and sliced onions earlier in the day to divide up the labor, and ended up refrigerating overnight prior to baking and serving. 12/10 highly recommend, so worth it.
SO happy you loved it! it’s probably my favorite mac and cheese recipe ever.
WOW! This was the winning dish at our Thanksgiving table. Such amazing flavors from the cheese combination and rich sweetness from the onions. I sliced the onions super thin and fully caramelized so they reduced down to less than 2 cups, but the flavor carried through the whole dish. I can’t wait to make this again for a potluck.
Yay! I’m so glad everyone loved it!
Deliciously elegant! Can this be made in advance?
Absolutely! You could make the soup several days in advance and just reheat a bit before getting it in the oven with the bread and cheese.