Introduction

French Onion Soup Mac & Cheese combines the rich, caramelized flavors of classic French onion soup with creamy, cheesy macaroni. This comforting dish elevates traditional mac and cheese with savory onions and a crispy breadcrumb topping, perfect for a cozy dinner.

The image shows a white bowl filled with creamy baked macaroni and cheese. The top layer is golden brown with crispy browned spots and herbs sprinkled on it. Beneath this, there is a thick, gooey cheese sauce that is smooth and stretches as a woman's hand with a fork lifts a serving. The macaroni pasta is visible in multiple layers, coated in the melty cheese sauce, which is a pale yellow with a shiny texture. The bowl sits on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

12 ounces elbow macaroni
3 large yellow onions, thinly sliced
2 tablespoons olive oil
3 tablespoons butter
2 cloves garlic, minced
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
1 teaspoon fresh thyme (or 1/2 teaspoon dried)
1 cup breadcrumbs
1/2 cup grated Parmesan cheese

Instructions

Step 1: Preheat your oven to 375°F (190°C) and butter a baking dish.
Step 2: Heat olive oil and 1 tablespoon of butter in a skillet over medium heat. Add the sliced onions and cook, stirring often, until caramelized, about 25–30 minutes. Stir in the minced garlic and thyme.
Step 3: Add the remaining butter to the skillet. Stir in the flour to create a roux, cooking for 1-2 minutes. Slowly whisk in the vegetable broth, then milk and heavy cream until the mixture is smooth and thickened.
Step 4: Stir in the Gruyère, cheddar, and mozzarella cheeses until melted and combined. Season with salt and black pepper.
Step 5: Cook the elbow macaroni according to package instructions until al dente. Drain and toss the pasta with the cheese sauce and caramelized onions.
Step 6: Transfer the mac and cheese mixture to the prepared baking dish. In a small bowl, combine the breadcrumbs and grated Parmesan cheese, then sprinkle evenly over the top.
Step 7: Bake in the preheated oven for 20–25 minutes until bubbly and golden brown on top.
Step 8: Let the dish rest for 5 minutes before serving. Garnish with additional fresh thyme if desired, and serve hot.

Tips & Variations

For extra depth, add a splash of dry white wine to the onion mixture while caramelizing.
Use a mix of cheeses you prefer, but Gruyère is key for that authentic French onion flavor.
Substitute vegetable broth with beef broth for a richer taste.
For a gluten-free version, use gluten-free pasta and substitute the flour with a gluten-free thickener.
Make ahead: Prepare the mac and cheese through step 5, then refrigerate. Add breadcrumbs and bake when ready to serve.

Storage

Store leftover French Onion Soup Mac & Cheese in an airtight container in the refrigerator for up to 3 days. Reheat in the oven at 350°F (175°C) until warmed through, or microwave in short intervals to avoid drying out. Adding a splash of milk before reheating helps maintain creaminess.

How to Serve

The image shows a close-up of a skillet filled with creamy macaroni and cheese. The top layer is golden brown and crispy with melted cheese stretching in strings as a spoon lifts some macaroni. The macaroni underneath is soft and coated in a thick, smooth white cheese sauce with small green herb bits scattered on top. The skillet sits on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use a different type of pasta?

Yes, any short pasta like shells, penne, or cavatappi works well with this recipe. Just make sure to cook it al dente so it doesn’t get mushy after baking.

Is there a vegetarian version of this recipe?

Absolutely. This recipe uses vegetable broth, which makes it vegetarian-friendly. Just be sure your cheeses do not contain animal rennet if you want it strictly vegetarian.

French Onion Soup Mac & Cheese Recipe

Print Recipe

★★★★★

4.6 from 94 reviews

This French Onion Soup Mac & Cheese combines the rich, caramelized flavors of classic French onion soup with creamy, cheesy macaroni for a comforting and indulgent twist on two beloved dishes. The slow-cooked onions and aromatic thyme infuse the creamy cheese sauce, which is baked to golden perfection with a crunchy breadcrumb and Parmesan topping.

Author: Tara
Prep Time: 15 minutes
Cook Time: 55 minutes
Total Time: 1 hour 10 minutes
Yield: 6 servings 1x
Category: Main Course
Method: Baking
Cuisine: French-American
Diet: Vegetarian

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)

Sauce

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

Topping

1 cup breadcrumbs
1/2 cup Parmesan cheese, grated

Instructions

Preheat Your Equipment: Preheat your oven to 375°F (190°C) and generously butter a baking dish to prevent sticking.
Caramelize Onions: Heat olive oil and 1 tablespoon of butter in a large skillet over medium heat. Add the thinly sliced onions and cook, stirring often, until they become deeply caramelized and golden brown, which takes about 25–30 minutes. Then stir in the minced garlic and thyme, cooking for about 1 more minute until fragrant.
Make the Roux and Sauce: To the skillet with the onions, add the remaining butter and let it melt. Stir in the flour to create a roux, cooking for 1–2 minutes while stirring to remove the raw flour taste. Slowly whisk in the vegetable broth, followed by the milk and heavy cream, ensuring the mixture is smooth and thickened.
Add the Cheese: Stir in the shredded Gruyère, cheddar, and mozzarella cheeses until melted and fully incorporated into the sauce. Season with salt and black pepper to taste.
Combine Pasta and Sauce: Toss the cooked al dente macaroni noodles with the cheese sauce and caramelized onions, making sure everything is evenly coated and combined.
Assemble in Baking Dish: Transfer the mac and cheese mixture into the prepared buttered baking dish. In a small bowl, mix the breadcrumbs with Parmesan cheese. Evenly sprinkle this topping over the mac and cheese.
Bake: Place the baking dish in the preheated oven and bake for 20–25 minutes, or until the top is golden brown and bubbly.
Serve: Remove from the oven and let the dish rest for 5 minutes. Garnish with extra fresh thyme if desired and serve hot for a comforting meal.

Notes

For the best flavor, allow the onions to caramelize slowly and patiently; rushing this step will result in less depth of flavor.
You can substitute vegetable broth with beef broth for a richer taste if not vegetarian.
To make ahead, assemble the dish, cover, and refrigerate up to 24 hours before baking.
Use day-old breadcrumbs for a crisper topping.
For a gluten-free version, use gluten-free flour and gluten-free breadcrumbs.

Keywords: French Onion Soup, Mac and Cheese, Caramelized Onions, Comfort Food, Baked Pasta, Cheese Sauce