Description
This French Onion Mac and Cheese combines the rich, caramelized flavors of sweet onions with creamy, cheesy pasta. The onions are slowly caramelized to bring out their natural sweetness and layered with a blend of Gruyere and Parmesan melted into a smooth béchamel sauce. Topped with seasoned breadcrumbs and baked to a golden bubbly finish, this dish is a comforting twist on a classic comfort food perfect for gatherings or indulgent weeknight meals.
Ingredients
Scale
Caramelized Onions
- 3 tablespoons olive oil
- 4 large sweet onions, thinly sliced
- Kosher salt and pepper, to taste
Pasta and Cheese Sauce
- 1 pound short cut pasta, cooked
- 3 tablespoons unsalted butter
- ¼ cup all-purpose flour
- 2 ½ cups milk
- ¼ teaspoon freshly ground nutmeg
- 12 ounces Gruyere cheese, freshly grated
- 4 ounces Parmesan cheese, freshly grated
Topping
- ⅓ cup seasoned bread crumbs
- Fresh thyme, for serving
Instructions
- Caramelize the Onions: Heat the olive oil in a large oven-safe skillet over medium heat. Add the thinly sliced onions with a generous pinch of kosher salt. Cook the onions, stirring frequently, until they begin to soften, about 10 to 15 minutes.
- Slowly Cook the Onions: Reduce the heat to low or medium-low and continue cooking the onions, stirring often to prevent burning, allowing them to caramelize and turn golden brown. This process takes approximately 60 to 90 minutes. If onions start to stick or burn, add small splashes of water to keep them moist. For faster caramelization, you may optionally add 1 teaspoon of sugar, honey, or maple syrup, stirring often to monitor progress.
- Prepare Pasta and Oven: Preheat your oven to 375°F (190°C). Meanwhile, boil the pasta according to package directions until al dente, then drain and set aside.
- Make the Roux and Sauce: In the same skillet used for onions, add the unsalted butter and melt over medium heat. Whisk in the flour to form a roux and cook for 2 to 3 minutes until it turns golden and smells nutty. Gradually pour in the milk while whisking constantly to avoid lumps. Continue stirring the sauce until it thickens smoothly. Stir in the freshly ground nutmeg.
- Add Cheeses and Onions: Mix in almost all of the grated Gruyere and Parmesan cheeses, saving a small amount for topping. Then fold in three-quarters of the caramelized onions. Combine the cheese sauce thoroughly with the cooked pasta by tossing gently to mix all elements evenly.
- Assemble and Bake: Spread the mac and cheese mixture evenly in the skillet or transfer to a baking dish. Sprinkle the remaining cheese and caramelized onions on top, then cover with the seasoned bread crumbs. Bake in the preheated oven for 25 to 30 minutes until the top is golden brown and the sauce is bubbly.
- Garnish and Serve: Remove from oven and sprinkle fresh thyme leaves over the top for a fragrant finish. Serve warm and enjoy!
Notes
- Adding a teaspoon of sugar, honey, or maple syrup to the onions can speed up caramelization if you are short on time.
- Use an oven-safe skillet for easy transfer from stove to oven.
- Make sure to stir the onions frequently during caramelization to prevent burning.
- Gruyere cheese provides a smooth, melty texture while Parmesan adds sharpness—don’t skip either.
- This dish can be prepared ahead; caramelize onions and make sauce, then assemble and bake when ready.
Nutrition
- Serving Size: 1 serving (approx. 1 cup)
- Calories: 420
- Sugar: 6g
- Sodium: 410mg
- Fat: 18g
- Saturated Fat: 9g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 45g
- Fiber: 3g
- Protein: 18g
- Cholesterol: 50mg
