Description

This French Onion Soup Mac & Cheese combines the rich, caramelized flavors of classic French onion soup with creamy, cheesy macaroni for an indulgent comfort food experience. Featuring a melty blend of Gruyère, sharp cheddar, and mozzarella cheeses, topped with a crunchy Parmesan breadcrumb crust, this baked dish is 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)

Sauce

3 tablespoons flour
2 cups vegetable broth
2 cups whole milk
1/2 cup heavy cream
Salt – 1 teaspoon
Black pepper – 1/2 teaspoon

Cheese

2 cups shredded Gruyère cheese
1 cup shredded sharp cheddar cheese
1 cup shredded mozzarella cheese

Topping

1 cup breadcrumbs
1/2 cup grated Parmesan cheese

Instructions

Preheat the oven and prepare baking dish: Preheat your oven to 375°F (190°C) and generously butter a baking dish to prevent sticking and help with even browning.
Caramelize the onions: Heat olive oil and 1 tablespoon of butter in a skillet over medium heat. Add the thinly sliced onions and cook, stirring frequently, until they become deeply caramelized and golden brown, about 25 to 30 minutes. Then stir in minced garlic and thyme for aromatic flavor.
Make the roux and sauce base: Add the remaining 2 tablespoons of butter to the skillet. Stir in the flour and cook briefly to form a roux. Gradually whisk in the vegetable broth, followed by the whole milk and heavy cream, ensuring the mixture is smooth and free of lumps.
Add the cheeses and season: Stir in Gruyère, sharp cheddar, and mozzarella cheese until they melt smoothly into the sauce. Season with salt and black pepper to taste.
Combine pasta and sauce: Toss the cooked al dente elbow macaroni with the cheese sauce and caramelized onions, ensuring everything is evenly coated.
Transfer and top: Pour the mac and cheese mixture into the prepared baking dish. Mix the breadcrumbs with grated Parmesan cheese, sprinkle this mixture evenly over the top to create a crispy topping.
Bake the casserole: Place the baking dish in the preheated oven and bake for 20 to 25 minutes, or until the top is golden brown and the dish is bubbling hot.
Rest and serve: Let the baked mac and cheese rest for 5 minutes to set. Garnish with fresh thyme leaves before serving hot for maximum flavor and visual appeal.

Notes

Caramelizing the onions slowly is key to developing that deep, rich French onion flavor.
Be sure to cook the pasta just until al dente since it will continue to cook in the oven.
You can substitute fresh thyme with dried thyme if needed, though fresh provides better aroma.
For extra richness, use full-fat dairy ingredients as specified.
Breadcrumb topping adds a crispy contrast; use panko for an even crunchier texture.
Letting the dish rest after baking helps it set and makes serving easier.

Prep Time: 15 minutes
Cook Time: 45 minutes
Category: Main Course
Method: Baking
Cuisine: French-American

Keywords: French onion soup, mac and cheese, caramelized onions, Gruyère, baked pasta, comfort food, cheesy casserole