Elevate your mac and cheese experience with this decadent French Onion Macaroni and Cheese. Imagine a creamy, cheesy sauce infused with the rich flavors of caramelized onions, tangy Gruyère cheese, and a hint of vibrant thyme. This dish is a perfect blend of comfort food and sophistication, guaranteed to be a crowd-pleaser. Post contains affiliate links.

When it comes to comfort food, my two absolute favorites are French Onion Soup and Creamy Macaroni and Cheese. So, you can imagine my excitement when I produced this idea to combine them! This French Onion Macaroni and Cheese is pure magic. The creamy, cheesy sauce is infused with the rich flavors of caramelized onions, just like my favorite soup, and it is all topped with a sprinkle of Gruyère cheese & garlicky ciabatta croutons for extra goodness. My husband loved this dish and 2/3 of my typically picky kids enjoyed it. My son, well he is just too picky-haha.
Why We Love this Recipe
- Flavor Explosion: The combination of caramelized onions, creamy cheese sauce, and tangy Gruyère creates a symphony of flavors that is truly irresistible.
- Elevated Comfort Food: This recipe takes a classic comfort food and elevates it with sophisticated flavors, making it a special occasion worthy dish.
- Easy to Make: Despite its gourmet taste, this recipe is surprisingly easy to prepare.
- Crowd-Pleaser: This dish is guaranteed to be a hit with family and friends of all ages.

Ingredients
- Onions – I used four large Vidalia sweet onions. I find these have the best flavor which adds a beautiful balance of sweet to the savory flavors.
- Garlic – I pressed two cloves of garlic into the onions as they caramelized.
- Butter – I used unsalted butter for caramelizing the onions, toasting the ciabatta, and making the roux.
- Worcestershire sauce – Used when caramelizing the onions. Adds a tasty flavor.
- Balsamic vinegar of Modena – A touch adds the perfect caramelization to the onions.
- Better than Bouillon Beef Base – A must for that depth of flavor the onions need to mimic French onion soup.
- Sherry – Dry sherry wine is used to deglaze the onions after caramelizing.
- Whole milk -This was used to make the cheese sauce.
- Gruyere Cheese – Adds an upscale, nutty, and delicious flavor.
- Swiss Cheese – My favorite cheese for French onion soup which worked well in this recipe.
- Flour – All-purpose flour helped to make the roux.
- Spices – Mustard powder, black pepper, salt, and garlic powder are used in this recipe.
- Pasta – A pound of elbow macaroni was the pasta I chose for this recipe.

Making French Onion Macaroni and Cheese
Caramelize the Onions:
- Melt 4 tablespoons of butter in a large pot or Dutch oven over medium-low heat.
- Add the sliced onions, and garlic. Add the Worcestershire sauce, balsamic vinegar, salt, and pepper. Cook, stirring occasionally, for 30-40 minutes, or until the onions are deeply golden brown and caramelized.
- In a measuring cup, mix the Better Than Bouillon Beef Base and sherry wine until dissolved. Add wine mixture to the onions to deglaze the pan scraping up any brown bits. Transfer the caramelized onions to a bowl; set aside.
Garlic Croutons
- Melt 2 tablespoons of butter in the microwave.
- Slice half a ciabatta baguette in half; wrap the other half for another serving.
- Slice remaining half into small slices and place them on an air fryer tray.
- Brush each with melted butter, and sprinkle with garlic powder, salt, and pepper.
- Air fry for 3-5 minutes per side, or until golden brown and crispy. Keep a close eye on them as air fryers can vary. You want the bread to be a toasty, golden brown so it can be turned into rough crumbs in the food processor.
- Once toasted, add slices to a food processor to rough chop crumbs. Set aside once done for after macaroni and cheese has been baked.
Make the Roux and Cheese Sauce:
- Melt 4 tablespoons of butter in the same pot.
- Whisk in the flour and cook for 1-2 minutes, stirring constantly, to create a roux.
- Gradually whisk in the milk, stirring continuously to prevent lumps.
- Bring the sauce to a simmer over medium heat, stirring constantly, until it thickens.
- Over the lowest heat, stir in ⅔ of the Gruyère and Swiss cheese until melted and smooth, and in ⅔ of the caramelized onions to the cheese sauce. The remaining cheese and onions will be used to top the macaroni and cheese before baking.

Assembling
- Add drained macaroni to deep baking dish.
- Pour over cheese and onion sauce; mix to combine.
- Top with remaining shredded cheeses, and onions.
- Bake at 375℉ for 25 minutes.
- Once done, top with garlic crouton crumbs.
- Serve warm and enjoy!

Variations
Cheese Swaps
- Sharp Cheddar: Replace Gruyère with sharp cheddar for a more classic mac and cheese flavor.
- Fontina: Add Fontina for a creamy, nutty twist.
- Provolone: For a touch of sharpness and meltiness.
- Three-Cheese Blend: Combine Gruyère, Cheddar, and Provolone for a multi-layered flavor.
Toppings
- Use panko bread crumbs mixed with melted butter, garlic powder, salt, and pepper for a quicker crouton topping.
- Add crispy bacon to the top for a savory twist.
Storing Leftovers
Cool Completely: Allow the macaroni and cheese to cool completely at room temperature before refrigerating. This helps prevent bacterial growth.
Store Properly: Transfer the cooled macaroni and cheese to an airtight container with a lid. If you’re using a large bowl, cover it tightly with plastic wrap or aluminum foil.
Reheating Tips:
- Microwave: Reheat in short bursts, stirring in between, to prevent uneven heating.
- Stovetop: Gently reheat in a saucepan over low heat, stirring occasionally, until warmed through.
- Oven: Reheat in a preheated oven at 350°F (175°C) until heated through and bubbly.
Freezing:
- Not Recommended: Freezing macaroni and cheese can alter the texture and flavor. The creamy sauce may separate, and the pasta can become mushy upon thawing.
- If you must freeze: Portion the macaroni and cheese into individual servings in freezer-safe containers or bags. Freeze for up to 2 months. Thaw overnight in the refrigerator before reheating.

French Onion Recipes to Try Today
- French Onion Soup
- French Onion Beefy Rice Casserole
- French Onion Ground Beef Casserole
- French Onion Chicken Casserole
- Air Fryer French Onion Pork Chops
- French Onion Dip
French Onion Macaroni and Cheese
Equipment
- 1 oven adjusted to the center rack position
- Measuring Cups & spoons
- 1 5-quart stockpot *to boil pasta
- large skillet or Dutch oven *to caramelize onions & make roux and cheese sauce
- 1 11 x 13 deep-walled casserole dish *must be deep-walled as this recipe makes a lot
- food processor *with cheese attachment
- Air Fryer *to toast the croutons
- garlic press
- Whisk
Ingredients
For the Caramelized Onions
- 4 large Vidalia sweet onions thinly sliced
- 2 cloves garlic pressed or minced
- 4 tablespoons unsalted butter
- 1 tablespoon worcestershire sauce
- 1½ teaspoons balsamic vinegar
- 1½ teaspoons Better Than Bouillon Beef Base
- ½ cup dry sherry wine
- ½ teaspoon fresh thyme
- salt & pepper *to taste
Roux and Cheese Sauce
- 4 tablespoons unsalted butter
- ½ cup all-purpose flour
- 4 cups whole milk
- 6 ounces Gruyère cheese shredded with food processor
- 16 ounces swiss cheese shredded with food processor
- ¼ teaspoon fresh thyme
- 1 teaspoon mustard powder
- ½ teaspoon salt
- ¼ teaspoon black pepper
- ¼ teaspoon garlic powder
Macaroni
- 1 pound elbow macaroni *cooked al dente
- ¼ teaspoon salt
Croutons
- ½ ciabatta baguette sliced into 8-10 small slices about ½ inch thick.
- 2 tablespoons unsalted butter *melted
- 1 teaspoon garlic powder
- ½ teaspoon fresh thyme
- salt & pepper *to taste
Instructions
Caramelize the Onions:
- Melt 4 tablespoons of butter in a large pot or Dutch oven over medium-low heat.
- Add the sliced onions, and garlic. Add the Worcestershire sauce, balsamic vinegar, salt, and pepper. Cook, stirring occasionally, for 30-40 minutes, or until the onions are deeply golden brown and caramelized.
- In a measuring cup, mix the Better Than Bouillon Beef Base and sherry wine until dissolved. Add wine mixture to the onions to deglaze the pan scraping up any brown bits. Transfer the caramelized onions to a bowl; set aside.
Garlic Croutons
- Melt 2 tablespoons of butter in the microwave.
- Slice half a ciabatta baguette in half; wrap the other half for another serving.
- Slice remaining half into small slices and place them on an air fryer tray.
- Brush each with melted butter, and sprinkle with garlic powder, salt, and pepper.
- Air fry for 3-5 minutes per side, or until golden brown and crispy. Keep a close eye on them as air fryers can vary. You want the bread to be a toasty, golden brown so it can be turned into rough crumbs in the food processor.
- Once toasted, add slices to a food processor to rough chop crumbs. Set aside once done for after macaroni and cheese has been baked.
Make the Roux and Cheese Sauce:
- Melt 4 tablespoons of butter in the same pot.
- Whisk in the flour and cook for 1-2 minutes, stirring constantly, to create a roux.
- Gradually whisk in the milk, stirring continuously to prevent lumps.
- Bring the sauce to a simmer over medium heat, stirring constantly, until it thickens.
- Over the lowest heat, stir in ⅔ of the Gruyère and Swiss cheese until melted and smooth, and in ⅔ of the caramelized onions to the cheese sauce. The remaining cheese and onions will be used to top the macaroni and cheese before baking.
Assembling
- Add drained macaroni to deep baking dish.
- Pour over cheese and onion sauce; mix to combine.
- Top with remaining shredded cheeses, and onions.
- Bake at 375℉ for 25 minutes.
- Once done, top with garlic crouton crumbs.
- Serve warm and enjoy!
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