Ever found yourself torn between making a creamy mac and cheese or a bubbling pot of French onion soup, then this French Onion Mac and Cheese is your answer. It’s the best of both comfort foods in one ridiculously flavourful dish. It’s got slow-caramelized onions, melty gruyère, and golden, bubbling cheese on top. It’s rich, savoury, just slightly sweet from the onions, and every bite tastes like it’s come straight from a cozy bistro.

This French Onion Mac and Cheese recipe is what happens when two comfort food icons come together, and it just works. The jammy caramelized onions bring that sweet and savoury French onion soup vibe, while the creamy sauce (thanks to gruyère, mozzarella, dijon, and a hit of onion bouillon) coats every noodle in cheesy perfection. And don’t even get me started on that broiled, bubbly top; it’s golden, crispy, and completely addictive. If you love my French Onion Dip or my Stuffed Pasta Shells, you already know I don’t mess around with flavour. This one’s next level.

😍 Why You’ll Love This French Onion Mac and Cheese

Ultimate comfort food: rich caramelized onions and creamy mac and cheese come together in one cosy dish.
Golden and bubbly: broiled cheese on top gives you that irresistible crispy crust.
Cheese lovers’ dream: two kinds of cheese, plus a broiled cheesy top? Say less.
Low fuss: it tastes like you spent all day cooking without actually doing that.

🧀 Ingredients To Make French Onion Mac and Cheese

Macaroni: cooked just until al dente. Short shapes like elbows, cavatappi, or shells also work.
Olive oil and butter: a combo of both gives you the best base for caramelizing onions and building a rich, glossy roux.
Milk: for that creamy sauce that still feels rich.
Gruyère cheese: the classic choice for French onion soup, it’s nutty, melty, and so savoury.
Mozzarella cheese: adds that signature gooey mac and cheese texture.
Yellow onions: thinly sliced and slowly caramelized to bring out that sweet, savoury French onion flavour.
Garlic: adds an aromatic punch that ties everything together.

Better Than Bouillon Sautéed Onion Base: this is the secret weapon; it deepens the whole dish and makes everything taste like it’s been simmering for hours.
Balsamic vinegar: just a splash to round out the sweetness of the onions and add a little tang.
Dijon mustard: helps cut through the richness and sharpens the cheesy sauce just slightly.
Fresh thyme: adds an earthy note that complements the onions perfectly.
Nutmeg: just a pinch adds a subtle warmth and depth.
Breadcrumbs: for a golden, crispy topping. Panko works or make your own homemade breadcrumbs.

✔ How To Make This French Onion Mac and Cheese Recipe

Start by prepping your onions. Peel and thinly slice all four yellow onions, then set them aside. To caramelize the onions, heat the olive oil and 1 tablespoon of butter in a large oven-safe pan over medium heat. Once the butter has melted, add the onions along with a pinch of salt and pepper. Cook them low and slow, stirring every few minutes, for about 10 to 15 minutes. They should start to soften and take on a golden colour.

Add the garlic and fresh thyme and cook for about 1 minute, just until the garlic becomes fragrant. Then stir in the balsamic vinegar and 1 tablespoon of the Sautéed Onion Better Than Bouillon. Let it all bubble together for another minute, then transfer the onions to a bowl and set aside.

Next, bring a large pot of salted water to a boil and cook your macaroni until just al dente, about a minute or two less than the package instructions. Drain and set aside.

🤝 Sammy’s Tip for French Onion Mac and Cheese

• For that final touch, broil the top for the last 1-2 minutes to get that crispy, golden crust.

Now, make the cheese sauce. In the same pan you used for the onions, melt the remaining 2 tablespoons of butter over medium heat. Once melted, whisk in the flour to form a roux. If the mixture looks too dry, you can add an extra tablespoon of butter to smooth it out. Cook the roux for about 1-2 minutes, just until it starts to turn golden.

Slowly pour in the milk while whisking continuously. Stir until the roux has fully melted into the milk and the sauce is smooth. Then add the second tablespoon of Sautéed Onion Better Than Bouillon, the dijon mustard, and a pinch of nutmeg. Bring the sauce to a gentle simmer and let it thicken slightly.

Once thickened, stir in most of the shredded cheese (save some for the top) and mix until fully melted and creamy. Turn off the heat and fold in your cooked macaroni and the caramelized onions. Stir until everything is well combined and coated in the sauce.

Top with the remaining shredded cheese and a layer of breadcrumbs. Pop the pan in the oven and bake at 375F for 15-20 minutes, or until golden and bubbling.

🗒 Variations

Make it spicy: add a pinch of cayenne or red pepper flakes to the cheese sauce for a subtle kick.
Switch up the cheese: try different cheeses based on your preference, like sharp white cheddar, fontina, or smoked gouda.

🗒 Substitutions

Pasta swap: use shells, cavatappi, or rigatoni instead of macaroni if that’s what you have.
Fresh thyme: dried thyme works in a pinch; use about 1 teaspoon.
Butter: use plant-based butter if you’d like.

🍴 Leftovers? Lucky you.

Store leftovers in an airtight container in the fridge for up to 4 days. Reheat gently in the oven or microwave.

🤔 FAQ’S

👩🏻‍🍳 Hungry For More? 

If you loved this French Onion Mac and Cheese recipe, then make sure to check out a few of my other favourites you may also love:

• Stuffed Pasta Shells
• Stuffed Eggplant
• Stuffed Onions (Onion Dolma)
• Skillet Lasagna
• Eggplant Parmigiana
• Roasted Red Peppers

💌 Let’s Stay Connected

Keep in touch with me on Instagram, TikTok, Facebook, and Pinterest! If you do make this creamy mac and cheese recipe (or any recipe of mine) don’t forget to leave a review.