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French Onion Mac and Cheese
Prep Time
10 mins
Cook Time
1 hr 25 mins
 
Inspired by the classic flavor of French onion soup, this French onion mac and cheese features deeply caramelized onions, melty Gruyere, and golden panko for a classic comfort food mash up.
Recipe Type: Dinner
Keyword: French onion mac and cheese
Makes: 8 servings
Author: Elizabeth Stark
Ingredients
  • 5 tablespoons unsalted butter divided
  • 3 large or 4 small yellow onions, trimmed, halved, and cut into paper thin half moons
  • 1 teaspoon Diamond Crystal kosher salt (halve if using another kind of salt), divided
  • 1/2 teaspoon freshly cracked black pepper
  • 4 sprigs thyme, plus more for garnish
  • 2 bay leaves, fresh or dried
  • 1/4 cup all-purpose flour
  • 4 cups whole milk, warmed
  • 2 tablespoons Worcestershire sauce (optional)
  • 16 ounces grated Gruyere
  • 8 ounces grated cheddar
  • 1 pound rigatoni, cavatappi, or large shell pasta, cooked 2 minutes less than recommended cook time
  • 1 cup panko breadcrumbs
Instructions

  1. Set a large, wide, deep-sided skillet or pot over medium heat. Melt 2 tablespoons butter and add the onions. Cover the skillet or pot (use foil, if needed), and cook for 5 minutes. Uncover, turn heat to medium-low, and add 1/2 teaspoon each salt and pepper, 4 sprigs thyme, and bay leaves. Cook, stirring frequently, for 40 - 60 minutes, or until onions are a deep caramel hue and sweet-tasting. Onions can be caramelized ahead and kept in the fridge until needed.

  2. While onions cook, preheat oven to 425 degrees F. Butter a 9 x 13-inch baking dish.
  3. Once the onions have caramelized, remove thyme sprigs and bay leaves. Turn heat up to medium, add 2 tablespoons butter and 1/2 teaspoon salt. Sprinkle flour over the onions and cook, stirring constantly for 2 minutes. Stirring often, gradually add the milk in half cup increments, bringing roux to a gentle simmer between additions. Keep adding milk and stirring until mixture has thickened, about 25 minutes.
  4. Meanwhile, cook pasta, drain, and tip into prepared baking dish.
  5. Remove skillet or pot from heat and fold grated cheese into the roux (reserve 1/4 cup grated cheese for topping). Pour cheese mixture over the pasta and gently toss.
  6. In a small bowl, combine the remaining tablespoon of butter with the panko and cheese. Smush the butter into the panko with your fingertips. Add a pinch each salt and pepper. Sprinkle panko mixture over top of the mac.
  7. Mac can be prepped up to this point, covered and refrigerated for 3 days. Give it 30 minutes to come to room temp before baking.
  8. Slide mac and cheese into the oven and bake until top is golden and filling is very bubbly, about 25 minutes. If desired garnish with thyme sprigs or leaves.