French Onion Creamy Baked Mac and Cheese + Video

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This creamy baked mac and cheese is bursting with caramelized onion flavor. Make this recipe tonight for the best ever cheesy comfort food!

mac and cheese in glass bowl with spoon

French Onion Mac and Cheese

Combine two delicious comfort foods into one amazing dish with French Onion Mac and Cheese. It’s a filling cheesy pasta full of caramelized onions,, and sure to warm you up on the coldest of nights.

There are plenty of other delicious ways to enjoy caramelized onions too! My Slow Cooker French Onion Soup is not only easy to make, but it’s budget-friendly too. You get so much flavor out on the onions, and don’t forget to top it with plenty of cheese!

For a savory-sweet side dish, make these Rosemary Roasted Onions. They’re perfectly caramelized and taste great as leftovers.

ingredients in bowls on cutting board

Recipe Tips for Creamy Baked Mac and Cheese

  • Salt the pasta water: It’s said your water should “taste like the ocean” for the best tasting pasta. Not only does it season the noodles, but it also helps reduce the amount of starch so they don’t stick together.
  • Perfectly Smooth Sauce: Adding the half and half slowly while whisking constantly prevents any lumps from forming. Allow the dairy to warm on the counter for a bit first to keep it from curdling when it hits the hot pan.
  • Shred Cheese Yourself: Because pre-bagged shreds have a preservative to prevent clumping, the cheese often has a waxy texture and doesn’t melt properly.


Watch the video in the recipe card at the bottom of this post to see how easy it is to make the creamiest mac and cheese!

french onions in pot

How to caramelize onions

Since onions naturally contain a lot of sugar, cooking them for a long period of time releases those sugars and brings out a richer overall flavor.

Just combine sliced or chopped onions with oil or butter and some spices if you’d like. Cook over low heat and stir frequently so nothing burns or sticks to the pan.

Also, be sure to leave them uncovered so the liquid that’s released can evaporate. Once they’ve condensed down and turned a deep brown color, they’re done!

Or, make a batch of slow cooker caramelized onions instead. There is less hands-on work, but you will need to start them early in the morning so they have enough time to cook.

caramelized onions in pot

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empty pot

French Onion Mac and Cheese FAQ

Baked mac and cheese keeps in the refrigerator for 3 to 4 days. Store it in the casserole dish, covered with foil, or transfer to a separate container with a lid.

For best results, reheat individual portions in a pan on the stove or pop the pan back in the oven until warmed through.

french onion mac and cheese in pat

Can I use bread cubes instead?

Yes, but be sure to use unseasoned ones so they don’t affect the overall flavor of the dish.

french onion mac and cheese close up

Make Ahead Instructions

You can certainly make the baked mac and cheese the day before, then reheat when you’re ready to serve. Or, simply make the caramelized onions ahead of time and store them in the refrigerator in a sealed container.

Then, proceed with the recipe as directed once you’re ready to cook. You will need to melt additional butter in the pan before making the sauce, about an equal amount to the flour.


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french onion mac and cheese up close

french onion mac and cheese

French Onion Creamy Baked Mac and Cheese + Video

Donna Elick
This creamy baked mac and cheese is bursting with caramelized onion flavor. Make this recipe tonight for the best ever cheesy comfort food!
5 stars from 1 review
Tried this recipe?Please comment and review!
Prep Time 15 mins
Cook Time 2 hrs 20 mins
Total Time 2 hrs 35 mins
Course Main
Cuisine American
Method Oven
Servings 16


  • 3 cups French Bread, diced
  • 1/4 cup olive oil
  • 16 ounces macaroni noodles
  • 8 tablespoons unsalted butter
  • 4 large sweet onions, sliced thin
  • 4 garlic cloves, sliced thin
  • 8 whole sprigs fresh thyme
  • 1 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 1/4 cup all-purpose flour
  • 4 cups half and half
  • 4 cups gruyere cheese, shredded
  • 3 cups white cheddar cheese, shredded
  • 1 tablespoon fresh parsley, chopped fine, optional


  • Preheat the oven to 375°F. 
  • In a large bowl toss the cubed bread with the olive oil. Pour this out onto a baking sheet and toast the bread for 12 minutes, flipping the bread halfway through until lightly golden brown. Set aside. Turn the oven off.
  • In a heavy bottom skillet (or dutch oven) with deep sides over medium-low heat, melt the butter. 
  • Add the onions, garlic, thyme, salt, and pepper, stir to combine. Once the onions are coated in the butter, turn the heat down to low and cook for 2 hours to caramelize the onions, uncovered. Stir frequently to make sure they do not burn. Onions are done when they are cooked down to about a cup and are a very deep brown color.
  • While the onions are browning, cook the pasta per the directions on the back of the box and drain well. 
  • Preheat the oven to 400°F. Spray a 9×13 baking dish with cooking spray, set aside.
  • When the onions are done cooking, discard the thyme sprigs, take out about ¼ cup of the onion mixture, and set aside. Add the flour to the pot and stir to combine in the fat, cook for 2 minutes. Slowly pour in the half & half, whisking constantly. 
  • Bring to a simmer to thicken and take off the heat. Stir in 1 cup of the Gruyere and the 3 cups of white cheddar cheese until melted. Mix the cheese sauce with the macaroni noodles and pour into the baking dish, smooth out the top.
  • Evenly distribute the leftover onions on top of the casserole. Top the casserole with the croutons. Add the remaining 3 cups of the Gruyere on top. 
  • Bake for 15-20 minutes until bubbly and the cheese is browned on top. Be careful not to burn the croutons. Garnish with optional parsley and serve.


Donna’s Notes

Baked mac and cheese will keep in the refrigerator for 3 to 4 days. Store covered or transfer to a separate container with a lid.
For best results, reheat individual portions in a pan on the stove or pop the pan back in the oven until warmed through.


Serving: 1 | Calories: 643cal | Carbohydrates: 56g | Protein: 26g | Fat: 35g | Saturated Fat: 19g | Cholesterol: 94mg | Sodium: 833mg | Sugar: 10g | Fiber: 3g | Calcium: 600mg | Iron: 3mg

All nutritional information is based on third party calculations and is only an estimate. Each recipe’s nutritional value will vary depending on the ingredients used, measuring methods, and portion sizes.

Tried this recipe?Let us know how it was!
titled collage for creamy baked mac and cheese

Originally published November 2020

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  1. Your dish seems great for a family's meeting, easy to prepare so I can do it with my kids. Thanks for sharing!

  2. This recipe sounds delicious,I'm afraid the 13 by 9 inch dish is to small, I will use a slightly larger one, thank you for the recipe

  3. 5 stars
    I was afraid this would be good but man was I wrong! This mac and cheese is so creamy and the onions really stand out! YUM!

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