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French Onion Mac and Cheese

French Onion Mac Cheese

This creamy French Onion Mac and Cheese combines caramelized onions, Gruyere and Parmesan cheese in a baked pasta dish with fresh thyme, delivering rich, comforting flavors with a golden crust.
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Prep Time 2 hours
Cook Time 30 minutes
Total Time 2 hours 30 minutes
Course Main Course, Side Dish
Cuisine American
Servings 12 people
Calories 550 kcal

Equipment

  • 1 large oven-safe skillet
  • 1 oven
  • 1 pot for boiling pasta
  • 1 whisk

Ingredients
  

  • 3 tablespoons olive oil
  • 4 large sweet onions thinly sliced
  • Kosher salt and pepper to taste
  • 1 pound short cut pasta cooked
  • 3 tablespoons unsalted butter
  • 1/4 cup all-purpose flour
  • 2 1/2 cups milk
  • 1/4 teaspoon freshly ground nutmeg
  • 12 ounces Gruyere cheese freshly grated
  • 4 ounces Parmesan cheese freshly grated
  • 1/3 cup seasoned bread crumbs
  • Fresh thyme for garnish

Instructions
 

  • Heat olive oil in a large oven-safe skillet over medium heat and stir in thinly sliced onions with a pinch of salt.
  • Cook onions, stirring frequently, until softened, about 10 to 15 minutes.
  • Reduce heat to low or medium-low and cook onions, stirring often, for 60 to 90 minutes until golden and caramelized, adding water if needed to prevent burning.
  • Preheat oven to 375°F (190°C) and boil pasta according to package instructions; drain and set aside.
  • Transfer caramelized onions to a plate to cool; optionally add sugar or syrup during caramelization to speed process if needed.
  • In the same skillet, melt butter and whisk in flour to form a roux; cook for 2 to 3 minutes until golden and nutty.
  • Gradually whisk in milk, stirring constantly until mixture thickens; add nutmeg.
  • Stir in most of the grated Gruyere and Parmesan cheese until melted.
  • Add three-quarters of the caramelized onions and cooked pasta to the cheese sauce; mix until well combined.
  • Top with remaining cheese and caramelized onions; sprinkle with seasoned bread crumbs.
  • Bake in preheated oven for 25 to 30 minutes until golden and bubbly.
  • Remove from oven, garnish with fresh thyme, and serve warm.

Notes

  • To speed caramelization, add a teaspoon of sugar or honey while cooking onions.
  • Store leftovers covered in refrigerator up to 3 days.
  • Reheat in oven for best texture.