Description
This French Onion Soup Mac & Cheese combines the rich, caramelized flavors of classic French onion soup with the creamy indulgence of mac and cheese. Featuring a luxurious cheese sauce made with Gruyère, sharp cheddar, and mozzarella, layered with tender elbow macaroni and topped with crispy Parmesan breadcrumbs, this comforting casserole is baked to golden perfection. Perfect for a cozy dinner that elevates comfort food to a gourmet experience.
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 leaves (or 1/2 teaspoon dried thyme)
Cheese Sauce
- 3 tablespoons all-purpose 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
- Prepare the Oven and Baking Dish: Preheat the oven to 375°F (190°C) and butter a baking dish evenly to prevent sticking and help with 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 often, until they become deeply caramelized, soft, and golden brown, which should take about 25–30 minutes. Stir in minced garlic and thyme during the last few minutes of cooking to release their aromas.
- Create the Roux and Sauce Base: Add the remaining 2 tablespoons of butter to the skillet. Once melted, whisk in the flour to create a roux, cooking it for about 1-2 minutes to remove the raw flour taste. Slowly pour in the vegetable broth while whisking continuously to avoid lumps, then add the milk and heavy cream gradually, stirring until the sauce is smooth and starts to thicken.
- Add Cheese and Season: Stir in the shredded Gruyère, sharp cheddar, and mozzarella cheeses until fully melted and combined into a rich, creamy cheese sauce. Season the mixture with salt and black pepper to taste.
- Combine Pasta and Sauce: Cook the elbow macaroni until al dente according to package instructions, then drain. Toss the cooked pasta into the cheese sauce along with the caramelized onions, mixing thoroughly to coat the pasta evenly.
- Assemble and Top: Transfer the cheesy pasta and onion mixture into the prepared baking dish. Mix the breadcrumbs with grated Parmesan cheese and sprinkle this topping evenly over the assembled casserole for a crispy, golden crust.
- Bake: Bake the dish in the preheated oven for 20–25 minutes until the top is bubbly and beautifully golden brown.
- Rest and Serve: Allow the baked mac and cheese to rest for 5 minutes to set. Garnish with additional fresh thyme leaves if desired, then serve hot and enjoy the comforting flavors.
Notes
- For extra flavor, try adding a splash of dry white wine to the onion caramelizing step.
- Swap vegetable broth for beef broth for a richer, more traditional French onion soup flavor, if not vegetarian.
- Use gluten-free flour and breadcrumbs to make this recipe gluten-free.
- To make ahead, assemble but do not bake. Cover and refrigerate for up to 24 hours, then bake before serving.
- Leftovers can be refrigerated for up to 3 days and reheated in the oven for the best texture.
