Name: This French Onion Mac and Cheese Combines Two Favorite Comfort Foods
Prep time: 50 min
Cook time: 1 h 25 min
Total time: 2 h 25 min
Yield: 12
Cuisine: American
Ingredients: 6 tablespoons unsalted butter, divided, plus more for greasing the dish; 1 teaspoon kosher salt, plus more for cooking the pasta; 1 pound large ridged elbow macaroni; 2 large sweet onions, thinly sliced lengthwise; 1/3 cup dry sherry; 1/4 cup all-purpose flour; 5 cups whole milk; 1 tablespoon roasted beef bouillon base (such as Better Than Bouillon), optional; 1 1/2 teaspoons garlic powder; 1 1/2 teaspoons onion powder; 1 1/2 teaspoons ground mustard; 1/2 teaspoon freshly ground black pepper; 14 ounces Gruyère cheese, shredded (about 3 1/2 cups), divided; 8 ounces white American cheese, shredded (about 2 cups); Fresh thyme leaves, optional

1 Butter a 9x13-inch baking dish and set aside.

2 Bring a large pot of salted water to a boil and cook the pasta until just shy of al dente, about 1 minute less than cooking time indicated on package. Drain and set aside.

3 While the pasta is cooking, melt 2 tablespoons of the butter in a large Dutch oven over medium-low heat. Add the onions and 1 teaspoon salt and cook, stirring occasionally, until the onions are very soft and deeply browned, 30 to 35 minutes. Add the sherry (or beef broth and apple cider vinegar) and cook, stirring constantly, until completely evaporated, about 1 minute. Transfer the onions to a small bowl and set aside. Rinse the Dutch oven and wipe dry.

4 Preheat the oven to 400°F.

5 Return the Dutch oven to medium heat and melt the remaining 4 tablespoons butter; add the flour and cook, whisking constantly, until it no longer smells raw, 1 to 2 minutes. Whisking constantly, add the milk in a thin, steady stream. Bring to a simmer over medium and cook, whisking often, until sauce has thickened and coats the back of a spoon, about 15 minutes. Whisk in the bouillon, if using, garlic powder, onion powder, ground mustard, and pepper. (If not using bouillon, stir in 1 1/2 teaspoons of kosher salt.) Remove from the heat and whisk in 2 1/2 cups of the shredded Gruyère plus all of the American cheese until smooth. Add 1 1/2 cups of the caramelized onions and the cooked pasta and stir until well combined.

6 Pour the pasta into prepared baking dish. Top evenly with the remaining caramelized onions and Gruyère. Cover with foil and bake until the cheese has melted and sauce is bubbling around edges, about 25 minutes. Remove the foil. Turn the oven to broil. Keeping the casserole on the same rack, broil until the cheese has browned, 3 to 5 minutes.

7 Let the casserole rest for 10 minutes before serving. Garnish with thyme, if desired, and serve. Refrigerate leftovers in an airtight container for 3 to 5 days. Love the recipe? Leave us stars and a comment below!