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A close-up showcases the creamy, cheesy texture of French Onion Soup Mac & Cheese, highlighting its golden-brown, bubbly top.

ULTIMATE FRENCH ONION SOUP MAC & CHEESE

This recipe combines the comforting flavors of mac and cheese with the rich, savory depth of French onion soup. Caramelized onions, Gruyere cheese, and a creamy cheese sauce elevate this classic dish to a new level of deliciousness. Perfect for a cozy night in or a crowd-pleasing potluck.
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Prep Time 30 minutes
Cook Time 1 hour
Total Time 1 hour 30 minutes
Servings: 6
Course: Main Course
Cuisine: American, French
Calories: 800
Ingredients Equipment Method Notes

Ingredients
  

  • 2 large yellow onions, thinly sliced
  • 2 tablespoons butter
  • 1 tablespoon olive oil
  • 1 teaspoon sugar
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1/4 cup dry sherry or white wine optional
  • 4 tablespoons butter
  • 4 tablespoons all-purpose flour
  • 3 cups milk
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1/4 teaspoon nutmeg optional
  • 8 ounces Gruyere cheese, shredded
  • 4 ounces sharp cheddar cheese, shredded
  • 2 ounces Parmesan cheese, grated
  • 1 pound elbow macaroni
  • 2 tablespoons chopped fresh thyme optional
  • French bread slices, for topping optional
  • 2 tablespoons melted butter, for topping optional

Equipment

  • Large, heavy-bottomed pot or Dutch oven
  • whisk
  • 9x13-inch baking dish
  • sharp knife
  • cutting board
  • Measuring spoons
  • Measuring cups
  • Grater
  • colander
  • Oven

Method
 

  1. Thinly slice the yellow onions.
  2. Melt 2 tablespoons of butter and 1 tablespoon of olive oil in a large, heavy-bottomed pot or Dutch oven over medium-low heat.
  3. Add the sliced onions, sugar, 1/2 teaspoon of salt, and 1/4 teaspoon of pepper. Stir to coat evenly.
  4. Cook the onions, stirring occasionally, for 30-45 minutes, or until they are a deep golden brown color and incredibly soft. If the onions start to stick or burn, reduce the heat and add a tablespoon or two of water.
  5. Deglaze the pot with dry sherry or white wine (if using). Scrape up any browned bits from the bottom of the pot. Let the wine simmer for a minute or two until it's almost evaporated. Set the caramelized onions aside.
  6. In the same pot (wipe it out if needed), melt 4 tablespoons of butter over medium heat.
  7. Whisk in the flour and cook for about 1-2 minutes, stirring constantly to create a roux.
  8. Slowly pour in the milk, whisking constantly to prevent lumps from forming. Keep whisking until the sauce is smooth and thickened, about 5-7 minutes.
  9. Reduce the heat to low and stir in 1/2 teaspoon of salt, 1/4 teaspoon of pepper, and nutmeg (if using).
  10. Add the Gruyere, cheddar, and Parmesan cheese, stirring until melted and smooth.
  11. Taste the sauce and adjust the seasoning as needed.
  12. Cook the elbow macaroni according to package directions until al dente.
  13. Drain the pasta well and set it aside.
  14. Add the cooked macaroni to the pot with the cheese sauce. Stir to coat the pasta evenly.
  15. Gently fold in the caramelized onions. Be careful not to overmix.
  16. Stir in the chopped fresh thyme (if using).
  17. Preheat your oven to 350°F (175°C).
  18. Pour the French Onion Soup Mac & Cheese into a greased 9x13 inch baking dish.
  19. Arrange slices of French bread over the top of the mac and cheese (if using). Brush the bread with melted butter.
  20. Bake for 20-25 minutes, or until the mac and cheese is bubbly and the topping is golden brown (if using).
  21. Let the mac and cheese cool for a few minutes before serving.
  22. Serve hot.

Notes

Don't skimp on the onions! Use good quality cheese. Don't overcook the pasta. Get creative with toppings like breadcrumbs, crispy fried onions, or crumbled bacon. Make it ahead of time and bake it later. Vegetarian: This recipe is already vegetarian! Gluten-Free: Use gluten-free pasta and a gluten-free all-purpose flour blend in the cheese sauce. Dairy-Free: Use plant-based butter, milk, and cheese alternatives. Spicy: Add a pinch of red pepper flakes to the cheese sauce for a little heat. Different Cheeses: Experiment with different types of cheese in the sauce like Fontina, provolone, or Gouda.