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French Onion Soup Mac & Cheese Recipe

5 from 87 reviews

This French Onion Soup Mac & Cheese combines the rich, caramelized flavors of traditional French onion soup with creamy, gooey mac and cheese. Featuring a velvety cheese sauce made from Gruyère, sharp cheddar, and mozzarella, topped with Parmesan breadcrumbs and baked to golden perfection, this comforting dish delivers a perfect balance of savory depth and creamy indulgence.

Ingredients

Scale

Pasta

  • 12 ounces elbow macaroni

Onion 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 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

  1. Preheat Your Equipment: Start by preheating your oven to 375°F (190°C) and generously butter a baking dish to ensure the mac and cheese doesn’t stick during baking.
  2. Caramelize the Onions: Heat olive oil and 1 tablespoon of butter in a large 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. This slow cooking develops the rich, sweet flavor signature to French onion soup. Stir in the minced garlic and thyme during the last few minutes to infuse the aroma.
  3. Make the Roux and Sauce: Add the remaining 2 tablespoons of butter to the skillet with the onions. Once melted, sprinkle the flour over the mixture and stir constantly to form a roux, cooking for about 1 to 2 minutes to remove the raw flour taste. Gradually whisk in the vegetable broth, then the whole milk and heavy cream, stirring continuously until the sauce is smooth and thickened.
  4. Add the Cheeses and Season: Lower the heat and stir in the shredded Gruyère, sharp cheddar, and mozzarella cheeses until fully melted into the sauce, creating a creamy cheese blend. Season the sauce with salt and black pepper to balance the flavors.
  5. Combine Pasta and Sauce: Cook the elbow macaroni until al dente according to package instructions. Drain and immediately toss the pasta into the cheese and onion sauce, ensuring every piece is well coated with the rich sauce and flavorful onions.
  6. Prepare for Baking: Transfer the macaroni mixture into the prepared buttered baking dish. In a small bowl, combine the breadcrumbs with the grated Parmesan cheese, then evenly sprinkle this mixture over the top of the mac and cheese to create a crisp, golden crust when baked.
  7. Bake: Place the dish in the preheated oven and bake for 20 to 25 minutes until the cheese sauce is bubbling around the edges and the breadcrumb topping is golden brown and crispy.
  8. Rest and Serve: Remove the mac and cheese from the oven and let it rest for 5 minutes to set slightly. Garnish with fresh thyme leaves if desired, then serve hot for a hearty, flavorful meal.

Notes

  • For extra flavor, use homemade vegetable broth or low-sodium broth.
  • To reduce cooking time, you can prepare caramelized onions ahead and refrigerate them.
  • Feel free to substitute some or all of the vegetable broth with beef broth for a more traditional French onion flavor, keeping dietary preferences in mind.
  • If you prefer a gluten-free version, use gluten-free pasta and flour alternatives for the roux and breadcrumbs.
  • Letting the mac and cheese rest after baking helps the sauce thicken and improves texture.

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