Description
This French Onion Mac and Cheese recipe combines the rich, caramelized flavors of slow-cooked sweet onions with creamy, cheesy pasta. A luscious blend of Gruyere and Parmesan cheese in a velvety roux-based sauce, topped with crispy seasoned bread crumbs and fresh thyme, baked to golden perfection. It’s a comforting, elegant twist on classic mac and cheese, perfect for gatherings or a cozy meal.
Ingredients
Scale
Onions and Pasta
- 3 tablespoons olive oil
- 4 large sweet onions, thinly sliced
- Kosher salt and pepper, to taste
- 1 pound short cut pasta, cooked according to package directions
Sauce
- 3 tablespoons unsalted butter
- ¼ cup all-purpose flour
- 2 ½ cups milk
- ¼ teaspoon freshly ground nutmeg
Cheeses and Topping
- 12 ounces Gruyere cheese, freshly grated
- 4 ounces Parmesan cheese, freshly grated
- ⅓ cup seasoned bread crumbs
- Fresh thyme, for serving
Instructions
- Caramelize the Onions: Heat olive oil in a large oven-safe skillet over medium heat. Add sliced onions and a big pinch of kosher salt. Cook, stirring frequently, until onions soften, about 10 to 15 minutes. Lower the heat to medium-low and continue cooking, stirring often, for 60 to 90 minutes until onions turn golden and caramelized. If they begin to burn, reduce heat or add a few splashes of water to maintain moisture.
- Preheat Oven and Boil Pasta: Preheat your oven to 375°F (190°C). While onions caramelize, boil the pasta according to package instructions until al dente, then drain.
- Make the Roux and Cheese Sauce: Once the onions are caramelized, transfer most of them to a plate, reserving about ¼ for topping. Add butter to the skillet with residual onion flavor. When melted, whisk in flour to form a roux. Cook for 2 to 3 minutes until golden and nutty smelling. Gradually pour in milk while whisking constantly to avoid lumps, allowing the sauce to thicken. Stir in freshly ground nutmeg.
- Add Cheese and Combine: Stir in almost all the Gruyere and Parmesan cheeses until melted and smooth, reserving some for topping. Mix in ¾ of the caramelized onions and then add the cooked pasta. Toss everything thoroughly in the sauce until well combined.
- Top and Bake: Sprinkle the remaining cheese and caramelized onions over the top, followed by the seasoned bread crumbs. Place skillet in the preheated oven and bake for 25 to 30 minutes until the dish is golden, bubbly, and the breadcrumbs are crisp.
- Serve: Remove from the oven and garnish with fresh thyme. Serve warm and enjoy the perfect blend of creamy, cheesy, and caramelized flavors.
Notes
- To speed up caramelization, add 1 teaspoon of sugar, honey, or maple syrup to onions, stirring frequently to prevent burning.
- This dish is best served fresh but can be stored covered in the fridge for up to 3 days; reheat in the oven to maintain crisp topping.
- Use an oven-safe skillet, such as cast iron or stainless steel, for easy transition from stovetop to oven.
- Short cut pasta types like elbow macaroni or small shells work best for this recipe.
Keywords: French Onion Mac and Cheese, caramelized onions, cheesy pasta bake, Gruyere mac and cheese, comfort food, baked mac and cheese