Description

A decadent twist on classic mac & cheese, this French Onion Soup Mac & Cheese combines rich caramelized onions with a creamy blend of Gruyère, cheddar, and mozzarella cheeses. Baked to golden perfection with a crunchy Parmesan breadcrumb topping, it’s a comforting and flavorful dish perfect for cozy dinners.

Ingredients

Scale

Pasta

12 ounces elbow macaroni

Onions and Aromatics

3 large yellow onions, thinly sliced
2 tablespoons olive oil
3 tablespoons butter (divided)
2 cloves garlic, minced
1 teaspoon fresh thyme (or 1/2 teaspoon dried thyme)

Cheese Sauce

3 tablespoons flour
2 cups vegetable broth
2 cups whole milk
1/2 cup heavy cream
2 cups shredded Gruyère cheese
1 cup shredded sharp cheddar cheese
1 cup shredded mozzarella cheese
1 teaspoon salt
1/2 teaspoon black pepper

Topping

1 cup breadcrumbs
1/2 cup grated Parmesan cheese

Instructions

Preheat Your Equipment: Preheat your oven to 375°F (190°C) and butter a baking dish to prepare it for the mac & cheese.
Caramelize Onions: In a skillet, heat olive oil and 1 tablespoon of butter over medium heat. Add the thinly sliced onions and cook, stirring often, for 25 to 30 minutes until they become deeply caramelized. Stir in minced garlic and thyme towards the end of cooking for aromatic flavor.
Make the Roux and Sauce: Add the remaining 2 tablespoons of butter to the skillet. Stir in the flour and cook briefly to form a roux. Slowly whisk in the vegetable broth, followed by the whole milk and heavy cream, whisking until the mixture is smooth and starts to thicken.
Add Cheeses and Season: Stir in the shredded Gruyère, sharp cheddar, and mozzarella cheeses until fully melted and smooth. Season the cheese sauce with salt and black pepper to taste.
Toss Pasta with Sauce and Onions: Cook the elbow macaroni until al dente according to package instructions. Drain and then toss the pasta with the prepared cheese sauce and caramelized onions until evenly combined.
Assemble the Casserole: Transfer the mac & cheese mixture into the buttered baking dish. In a small bowl, combine breadcrumbs with grated Parmesan cheese and sprinkle this topping evenly over the mac & cheese.
Bake to Finish: Bake in the preheated oven for 20 to 25 minutes until the top is bubbly and golden brown.
Rest and Serve: Let the dish rest for 5 minutes after baking. Garnish with fresh thyme if desired, then serve hot and enjoy your rich French Onion Soup Mac & Cheese.

Notes

Caramelizing onions slowly is key to developing the deep, sweet flavor reminiscent of French onion soup.
Use freshly shredded cheese for better melting and flavor.
Breadcrumb topping adds a satisfying crunch and can be made gluten-free by using gluten-free breadcrumbs if desired.
If you want a stronger thyme flavor, use fresh thyme rather than dried.
Whole milk and heavy cream create a rich, creamy sauce; for a lighter version, you can substitute lower-fat dairy, but the texture may be less creamy.
Allowing the baked mac & cheese to rest helps it set slightly, making it easier to serve.

Prep Time: 15 minutes
Cook Time: 55 minutes
Category: Main Dish
Method: Baking
Cuisine: American

Keywords: French Onion Soup, Mac and Cheese, Baked Macaroni and Cheese, Comfort Food, Caramelized Onions, Gruyère Cheese