This French onion mac and cheese is a decadent take on classic macaroni and cheese inspired by French onion soup. Caramelized onions, a silky gruyère cheese sauce, fresh thyme and tender pasta come together in a baked, indulgent side dish.
Just when you thought mac and cheese couldn’t get any better…
I present to you: French onion mac and cheese!
Deeply caramelized onions. A silky gruyère cheese sauce with garlic and thyme. Tender noodles coated in velvety cheese and baked until bubbly and golden.
This recipe is outrageously good—sweet, savory and rich all at once.
I’ve dressed many dishes in French onion flavors, but turning mac and cheese into a French onion version feels especially perfect: caramelized onions, noodles and cheese are a natural match.
Whether or not mac and cheese is a family tradition at your holiday table, this version makes a luxurious once-a-year side or a comforting main that’s great with a big green salad.
Because this isn’t a standard dish on my family’s very traditional Thanksgiving, I like to experiment with it—flavors, textures and toppings—so the mac and cheese becomes something special and memorable.
This is the indulgent side dish you save for holidays and celebrations.
This is how I make it
I make this in one large oven-safe pan or Dutch oven. First, caramelize the onions—this takes time (about 60–90 minutes) and patience. Cook them low and slow, stirring often; a few splashes of water help prevent burning and encourage even browning.
Once the onions are deeply golden and caramelized, remove them and use the same pan to make the cheese sauce. I make a simple roux with butter and flour, stream in milk until it thickens, then stir in freshly grated gruyère and a little Parmesan for depth. Season with freshly ground nutmeg and black pepper.
Cook the pasta while the onions caramelize so it’s ready when the sauce is finished. Fold the pasta into the cheese sauce, then stir in most of the caramelized onions. Transfer to an oven-safe dish or leave in the pan, top with the remaining cheese and onions, then sprinkle seasoned breadcrumbs on top for crunch.
Bake at 375°F for about 25–30 minutes until bubbling and golden. Finish with fresh thyme and serve immediately.
Caramelized, crispy onions on top add texture and an extra hit of sweet-savory flavor.
This dish serves many people and feels rich and celebratory—perfect for holidays or any time you want a special comfort food.
Below is the full recipe and straightforward instructions so you can recreate this at home.
French Onion Mac and Cheese
French Onion Mac and Cheese
12 people
Ingredients
- 3 tablespoons olive oil
- 4 large sweet onions, thinly sliced
- Kosher salt and pepper, to taste
- 1 pound short cut pasta, cooked
- 3 tablespoons unsalted butter
- 1/4 cup all-purpose flour
- 2 1/2 cups milk
- 1/4 teaspoon freshly ground nutmeg
- 12 ounces gruyère cheese, freshly grated
- 4 ounces Parmesan cheese, freshly grated
- 1/3 cup seasoned bread crumbs
- Fresh thyme, for serving
Instructions
- Heat the olive oil in a large oven-safe skillet over medium heat. Add the sliced onions and a big pinch of salt. Cook, stirring often, until the onions begin to soften, about 10–15 minutes.
- Reduce the heat to low or medium-low and continue to cook the onions, stirring frequently, for 60–90 minutes until deeply golden and caramelized. If the onions start to stick or scorch, lower the heat or add a few splashes of water.
- Preheat the oven to 375°F (190°C). Boil the pasta according to package directions and drain.
- When the onions are caramelized, transfer most of them to a plate, reserving a portion for topping. (If short on time, 1 teaspoon of sugar, honey or maple syrup can help speed caramelization—stir and watch closely.)
- Add the butter to the skillet and melt. Whisk in the flour to make a roux and cook 2–3 minutes until golden and nutty. Gradually whisk in the milk, stirring constantly, until the sauce thickens. Stir in the nutmeg.
- Remove the pan from the heat and stir in almost all of the cheese, reserving some for the top. Add about three-quarters of the caramelized onions and the cooked pasta. Toss until well combined.
- Top with the remaining cheese and onions, then sprinkle the bread crumbs evenly over the surface. Bake 25–30 minutes until golden, bubbly and heated through.
- Remove from the oven, sprinkle with fresh thyme and serve immediately.
Best dish ever.