French Onion Mac and Cheese
Tender macaroni is coated in a rich, creamy cheese sauce.Slow-caramelized onions provide deep sweetness and savory flavor.Gruyère adds a nutty, luxurious French-inspired character.Sharp cheddar brings classic mac and cheese richness.A buttery breadcrumb topping creates an irresistible golden crust.Perfect for holidays, family dinners, potlucks, and comfort-food cravings.
Ingredients
For the Caramelized Onions
- 3 large yellow onions, thinly sliced
- 3 tablespoons unsalted butter
- 1 tablespoon olive oil
- ½ teaspoon salt
- 1 teaspoon granulated sugar, optional
- ½ teaspoon dried thyme
- ¼ teaspoon black pepper
- 2 tablespoons dry white wine or beef/chicken broth, optional
For the Mac and Cheese
- 1 pound elbow macaroni or cavatappi
- 4 tablespoons unsalted butter
- ¼ cup all-purpose flour
- 2½ cups whole milk
- 1 cup heavy cream
- 1 teaspoon Dijon mustard
- ½ teaspoon garlic powder
- ½ teaspoon onion powder
- ½ teaspoon smoked paprika
- ½ teaspoon salt
- ¼ teaspoon black pepper
- 2 cups shredded Gruyère cheese
- 1½ cups shredded sharp cheddar cheese
For the Topping
- 1 cup panko breadcrumbs
- 2 tablespoons melted butter
- ¼ cup grated Parmesan cheese
- ½ teaspoon dried thyme
- ¼ teaspoon black pepper
For Garnishing
- Fresh thyme
- Extra caramelized onions
- Freshly cracked black pepper
- Additional grated Gruyère
Instructions
Prepare the Onions
- Heat the butter and olive oil in a large, heavy-bottomed skillet over medium-low heat.Add the thinly sliced onions and salt.Stir well to coat the onions with the butter and oil.
Slowly Caramelize the Onions
- Cook the onions over medium-low heat for approximately 35–45 minutes, stirring every few minutes.Initially, the onions will soften and release moisture. Gradually, they will become golden brown and deeply caramelized.If the onions begin sticking too much, add a tablespoon of water or broth and scrape the bottom of the pan.
Add Seasonings
- Once the onions are deeply golden, stir in the thyme and black pepper.Add the sugar if desired for a slightly sweeter caramelized flavor.If using wine or broth, pour it into the pan and stir, scraping up any flavorful browned bits.Cook for another 1–2 minutes.Remove from the heat and set aside.
Cook the Pasta
- Bring a large pot of generously salted water to a boil.Add the macaroni and cook according to the package instructions until just al dente.Do not overcook the pasta because it will continue cooking in the oven.Drain thoroughly.
Add the Cheese
- Reduce the heat to low or remove the saucepan from direct heat.Add the Gruyère, cheddar, and mozzarella gradually.Stir until the cheese is completely melted and the sauce is smooth and creamy.Avoid boiling the sauce after adding the cheese.
Combine Pasta and Cheese Sauce
- Add the drained macaroni to the cheese sauce.Stir gently until every piece of pasta is coated.Fold in approximately half of the caramelized onions.
Assemble the Casserole
- Preheat the oven to 375°F (190°C).Grease a 9×13-inch baking dish.Transfer half of the macaroni mixture to the dish.Add a layer of caramelized onions.Top with the remaining macaroni.Finish with the remaining onions and a small amount of shredded Gruyère.
Bake
- Place the casserole in the preheated oven.Bake uncovered for approximately 25–30 minutes, until the edges are bubbling and the breadcrumb topping is golden brown.
Rest and Garnish
- Remove the casserole from the oven.Allow it to rest for 5–10 minutes.Garnish with fresh thyme and freshly cracked black pepper.Serve warm.
Notes
- Caramelization takes time: Avoid rushing the onions with excessively high heat.
- Use yellow onions: They develop a naturally sweet and savory flavor when caramelized.
- Gruyère: This provides the nutty flavor that makes the dish reminiscent of French onion soup.
- Pasta: Cook it just until al dente so it does not become mushy in the oven.
- Cheese: Freshly shredded cheese generally melts more smoothly.
- Wine: Wine is optional; broth can be used instead.
- Breadcrumbs: Panko provides a particularly light and crunchy topping.
- Resting: Let the casserole rest briefly before serving so the sauce can settle.