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Nicole's French Onion Mac and Cheese

This mac and cheese provides the rich flavor of French onion soup in a comforting new package. This is a great dish to serve for an elegant entertaining meal or as a side dish to a grilled steak.
Print Recipe
Prep Time 15 minutes
Cook Time 1 hour 35 minutes
Total Time 1 hour 50 minutes
Course lunch/dinner
Cuisine American, French
Servings 8 people
Calories 4745.3 kcal

Equipment

  • 1 Large Skillet For caramelizing onions and preparing the cheese sauce.
  • 1 Large Pot For cooking the elbow macaroni.
  • 1 Whisk Essential for smooth béchamel sauce.
  • 1 9x13 inch Baking Dish For assembling and baking the mac and cheese.
  • 1 Cutting Board and Knife For thinly slicing onions and baguette.

Ingredients
  

Main

  • 6 tablespoons butter divided
  • 1 tablespoon olive oil
  • 2 large sweet onions thinly sliced
  • 2 teaspoons fresh thyme leaves
  • 2 teaspoons Worcestershire sauce
  • 1 tablespoon dry sherry
  • 1 tablespoon kosher salt divided
  • 1 teaspoon ground black pepper divided
  • 1 12 ounce package elbow macaroni
  • ¼ cup all-purpose flour
  • 2 ½ cups whole milk
  • 2 cups shredded white Cheddar cheese divided
  • 2 cups shredded Swiss cheese divided
  • ¼ French baguette cut into 1/2-inch slices

Instructions
 

  • Heat 2 tablespoons butter and olive oil in a large skillet over medium heat. Add onions and cook, stirring constantly, for 1 minute. Reduce heat to medium-low and cook, stirring occasionally, until golden brown, about 40 minutes.
  • Add thyme, Worcestershire, and sherry and cook until most of the liquid has evaporated, about 3 minutes. Season with 1/2 teaspoon salt and 1/2 teaspoon pepper. Remove onions from the pan and set aside. Reserve skillet.
  • Bring a large pot of water to a boil and add 2 teaspoons salt. Add pasta and cook until tender, about 6 minutes. Drain and set aside.
  • Preheat the oven to 375 degrees F (190 degrees C). Butter a 9x13-inch or 3-quart baking dish.
  • Place the reserved skillet over medium heat and add remaining butter. When butter has melted, whisk in flour and cook, stirring often, 2 minutes. Whisk in milk and bring mixture to a simmer, stirring often. Sprinkle with remaining salt and pepper and cook 5 minutes, stirring often. Stir in 1 1/2 cups Cheddar and 1 cup Swiss cheese and remove from heat.
  • Stir in reserved onions and pasta and pour mixture into the buttered baking dish. Tear bread slices in half and place over the top of the pasta mixture. Sprinkle with remaining cheeses.
  • Bake in the preheated oven until golden and bubbly, about 25 minutes.

Notes

Achieving deeply caramelized onions is crucial; take your time with medium-low heat to develop rich, complex flavor, about 40 minutes is accurate. The Worcestershire and sherry add depth, mimicking classic French onion soup notes. When making the béchamel, ensure the flour cooks out for at least 2 minutes to avoid a raw flour taste. For an even creamier sauce, bring milk to a simmer before whisking into the roux. Consider adding a pinch of nutmeg to the cheese sauce for an authentic French touch. For enhanced texture, toast the baguette slices lightly before topping the casserole, or brush with garlic butter for extra flavor.