Ingredients

Instructions

  1. Preheat the oven to 350º.
  2. In a large pot of boiling salted water, cook the pasta until al dente, about 11 minutes (or as directed on package).
  3. Meanwhile, heat a large, heavy-bottomed saucepan over medium-high heat.
  4. Add the sausage and cook, stirring and breaking up the meat with a wooden spoon, until no longer pink, 3 to 4 minutes.
  5. Transfer the sausage to a large bowl and wipe the saucepan clean.
  6. Add the pasta and 1 cup caramelized onions to the sausage and stir to combine.
  7. In a medium saucepan or a microwave oven, heat the milk until steaming.
  8. Return the large saucepan to the stove, add the butter and melt over medium heat.
  9. Add the flour and cook, whisking constantly, for 3 minutes.
  10. Whisk in the hot milk, 1/4 cup at a time, and continue whisking until the sauce is smooth and thick and comes to a simmer.
  11. Add 2 1/2 cups cheese, remove from the heat and whisk until the cheese is melted, about 2 minutes; season to taste with salt and pepper.
  12. Add the cheese sauce to the pasta mixture and stir to combine.
  13. Butter a 9-by-13-inch baking dish and add the pasta mixture in an even layer. Sprinkle the remaining 1/2 cup caramelized onions and 1 1/2 cups cheese on top.
  14. Bake until golden and bubbling, about 40 minutes.
  15. Remove from the oven and let rest for 10 minutes before serving.