- 1 Tbsp. unsalted butter
- 4 slices white bread, cut into ½" squares
- Kosher salt
- Unsalted butter, for greasing pan
- 2 cups elbow pasta
- 8 ounces Cheddar cheese, shredded
- 8 ounces Colby cheese, shredded
- 8 ounces pepper Jack cheese, shredded
- 2 tsp. all-purpose flour
- ½ tsp. kosher salt
- ½ tsp. ground black pepper
- ½ tsp. cayenne pepper
- ½ tsp. dry mustard
- ⅛ tsp. ground nutmeg
- ¼ cup sour cream
- 1 large egg, beaten
- ¼ cup grated sweet onion
- 1 cup heavy cream
- 1 cup half-and-half
DirectionsActive time: 20 minutes
Total time: 70 minutes
To make croutons: In a large skillet, melt butter over medium heat. Add bread; stir until golden. Drain on a paper towel-lined plate and season with a pinch of salt. Set aside.
To make pasta: Preheat oven to 350°. Butter a 9" x 13" baking dish. Bring a large pot of salted water to a boil and cook pasta until almost al dente; drain, then return pasta to pot. In a medium bowl, combine Cheddar, Colby, and Jack. Mix 2/3 of cheese with pasta. Set aside.
In a large bowl, combine flour, salt, black pepper, cayenne, mustard, nutmeg, sour cream, egg, onion, heavy cream, and half-and-half. Pour over pasta and mix. Transfer to baking dish and scatter remaining cheese over top. Bake uncovered until just beginning to brown, about 35 minutes. Top with croutons and bake until golden brown, about 10 minutes more. Let sit 15 minutes before serving.