Description
A decadent twist on the classic comfort food, French Onion Soup Mac & Cheese combines rich caramelized onions, a creamy trio of melted cheeses, and savory herbs baked to bubbly perfection. This hearty casserole offers the deep flavors of French onion soup in a cheesy, satisfying pasta dish perfect for cozy dinners.
Ingredients
Scale
Pasta
- 12 ounces elbow macaroni
Onion Soup Base
- 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)
Sauce
- 3 tablespoons all-purpose flour
- 2 cups vegetable broth
- 2 cups whole milk
- 1/2 cup heavy cream
Cheeses
- 2 cups Gruyère cheese, shredded
- 1 cup sharp cheddar cheese, shredded
- 1 cup mozzarella cheese, shredded
- 1/2 cup Parmesan cheese, grated
Other
- 1 teaspoon salt
- 1/2 teaspoon black pepper
- 1 cup breadcrumbs
Instructions
- Prepare Oven and Baking Dish: Preheat your oven to 375°F (190°C) and butter a baking dish to prevent sticking and prepare for the final bake.
- Caramelize Onions: In a skillet, heat olive oil and 1 tablespoon of butter over medium heat. Add the thinly sliced onions and cook, stirring frequently, for about 25–30 minutes until they become golden brown and caramelized. Stir in the minced garlic and thyme at the end to release their aromas.
- Make Roux and Sauce: Add the remaining 2 tablespoons of butter to the skillet with onions. Stir in the flour to create a roux, cooking until it forms a paste. Gradually whisk in the vegetable broth, followed by the whole milk and heavy cream, to form a smooth, thickened sauce.
- Add Cheese and Season: Stir in the shredded Gruyère, cheddar, and mozzarella cheeses until the sauce is creamy and the cheeses are melted. Season with salt and black pepper to taste. Combine the cooked elbow macaroni (cooked al dente) with the cheese sauce and caramelized onions, mixing well.
- Assemble and Top: Transfer the mac and cheese mixture to the prepared baking dish. Mix the breadcrumbs with the grated Parmesan cheese, then evenly sprinkle this topping over the pasta.
- Bake: Place the baking dish in the preheated oven and bake for 20–25 minutes until the top is golden brown and the sauce is bubbly.
- Serve: Remove from oven and let the dish rest for 5 minutes. Garnish with fresh thyme leaves if desired, then serve hot for a comforting meal.
Notes
- For best flavor, use freshly grated cheeses rather than pre-shredded, which often contain anti-caking agents.
- Caramelizing the onions slowly is key to developing the rich, sweet base essential for French Onion flavor.
- Make sure to cook the pasta al dente as it will continue to cook slightly when baked in the sauce.
- This dish can be made ahead and refrigerated; bake just before serving, adding a few extra minutes of baking time if cold.
- Vegetarian if you use vegetable broth, but not vegan due to cheese and dairy.
