French Onion Mac and Cheese

• •10 oz cavatappi or elbow macaroni
• •3 large yellow onions, thinly sliced
• •4 tablespoon unsalted butter, divided
• •1 tablespoon olive oil
• •2 garlic cloves, minced
• •1 tablespoon fresh thyme leaves, chopped
• •0.3 cup dry white wine (such as Sauvignon Blanc or Pinot Grigio)
• •0.5 cup low-sodium beef broth
• •3 tablespoon all-purpose flour
• •2 cup whole milk, warm
• •0.5 cup heavy cream
• •1 teaspoon Dijon mustard
• •0.5 teaspoon Worcestershire sauce
• •0.1 teaspoon freshly grated nutmeg
• •2 cup Gruyère cheese, freshly shredded and divided
• •1 cup sharp white cheddar cheese, freshly shredded
• •1 cup stale French baguette, pulsed into coarse breadcrumbs
• • to taste salt
• • to taste freshly cracked black pepper

Instructions

1. 1

   In a large Dutch oven or heavy-bottomed skillet, melt 2 tablespoons of butter with the olive oil over medium-low heat. Add the sliced onions and a pinch of salt. Cook slowly, stirring occasionally, for 30 to 35 minutes until the onions turn deep golden-brown and caramelized.

2. 2

   Stir in the minced garlic and chopped thyme; cook for 1 minute until fragrant. Pour in the dry white wine to deglaze the pan, scraping up any browned bits from the bottom. Add the beef broth and simmer for 3 to 4 minutes until the liquid is mostly reduced and absorbed by the onions. Remove half of the onions and set aside for topping.

3. 3

   Meanwhile, bring a large pot of salted water to a boil. Cook the pasta 1 to 2 minutes short of the package directions (very al dente). Drain and set aside.

4. 4

   To make the sauce, push the remaining caramelized onions in the pot to one side and melt 2 tablespoons of butter over medium heat. Whisk in the flour and cook for 1 to 2 minutes to create a roux.

5. 5

   Gradually pour in the warm milk and heavy cream, whisking continuously to prevent lumps. Bring to a gentle simmer and cook for 3 to 5 minutes until thickened enough to coat the back of a spoon.

6. 6

   Remove the sauce from heat. Whisk in the Dijon mustard, Worcestershire sauce, nutmeg, salt, and black pepper. Stir in 1.5 cups of the shredded Gruyère and all of the white cheddar cheese until melted and smooth.

7. 7

   Fold the cooked pasta into the cheese sauce until thoroughly coated. Transfer the mixture into a greased 2-quart baking dish (or leave in an oven-safe cast iron/Dutch oven).

8. 8

   Scatter the reserved caramelized onions over the top. In a small bowl, toss the coarse baguette breadcrumbs with 1 tablespoon of melted butter, then scatter the breadcrumbs and remaining 0.5 cup of Gruyère over the surface.

9. 9

   Bake at 375°F (190°C) for 15 to 20 minutes until bubbling around the edges. Turn on the broiler for 2 to 3 minutes to achieve a deeply golden, toasted crouton-like crust. Let rest 5 minutes before serving garnished with extra fresh thyme.

Chef's Tips

• 💡Do not rush caramelizing the onions; low and slow heat brings out the natural sugars essential for that authentic French onion flavor.
• 💡Grate the Gruyère and cheddar by hand from blocks, as pre-shredded cheese contains anti-caking agents that prevent a silky-smooth melt.
• 💡Using a splash of beef broth provides the savory umami backbone traditional to French onion soup.