Caramelized Onion Mac and Cheese
 
 
Serves: 8 to 10 servings
Ingredients
  • 1 cup crumbled cornbread
  • 1¾ cups shredded Gruyère cheese, divided
  • 2 tablespoons unsalted butter, melted
  • 3 teaspoons kosher salt, divided
  • 1½ teaspoons chopped fresh thyme, divided
  • 5 tablespoons unsalted butter, divided
  • 1½ large red onions, thinly sliced (about 1 pound)
  • 3 cloves garlic, chopped
  • 1½ tablespoons apple cider vinegar
  • 1 tablespoon honey
  • 3 tablespoons all-purpose flour
  • 2½ cups whole milk, room temperature
  • 4½ cups shredded sharp white Cheddar cheese
  • 1 teaspoon dry mustard
  • 1 teaspoon ground black pepper
  • 1 (16-ounce) package penne pasta, cooked according to package directions
  • Garnish: fresh thyme
Instructions
  1. Preheat oven to 425°.
  2. In a small bowl, combine cornbread crumbles, ½ cup Gruyère, melted butter, ½ teaspoon salt, and ½ teaspoon thyme.
  3. In a 12-inch cast-iron skillet, heat 2 tablespoons butter over medium-high heat. Add onion; cook, stirring occasionally, until lightly browned, 8 to 10 minutes. Add garlic; cook for 3 to 4 minutes, stirring frequently. Stir in vinegar, honey, and remaining 1 teaspoon thyme; cook until liquid is mostly absorbed, 1 to 2 minutes. Transfer onion mixture to a bowl. Wipe skillet clean.
  4. Melt remaining 3 tablespoons butter in skillet over medium heat. Add flour; cook, stirring constantly with a silicone whisk or wooden spoon, until golden and bubbly, 1 to 2 minutes. Gradually add milk, and increase heat to medium-high; cook, stirring frequently, until thickened, 6 to 8 minutes. Remove from heat. Gradually whisk in Cheddar and remaining 1¼ cups Gruyère. (Sauce will be thick.) Add mustard, pepper, and remaining 2½ teaspoons salt. Stir in cooked pasta and onion mixture. Top with cornbread mixture.
  5. Bake until topping is golden brown, about 10 minutes. Garnish with thyme, if desired.
Recipe by Southern Cast Iron at https://www.southerncastiron.com/caramelized-onion-mac-and-cheese/