sausage and spinach alfredo... 1 hour and 30 minutes

the goods:

1 pound elbow macaroni

5 tablespoons unsalted butter

6 tablespoons all-purpose flour

4 cups whole milk, room temperature

3/4 teaspoon ground mustard

1/2 teaspoon Old Bay seasoning

8 ounces white cheddar, shredded

4 ounces Monterey Jack, shredded

1/2 ounce Parmesan, grated (1/4 cup)

1 tablespoon extra-virgin olive oil

1 medium red onion, halved and thinly sliced

1/2 pound sweet Italian sausages, casings removed

1/2 teaspoon red-pepper flakes

2 tablespoons heavy cream

5 ounces baby spinach

shredded Parmesan, for serving

In a large pot of boiling salted water, cook macaroni according to package instructions. Drain.

In pot, melt 4 tablespoons butter over medium. Whisk in flour and cook, stirring frequently, until mixture is pale golden and has a nutty aroma, about 4 minutes.

Whisking constantly, slowly add milk. Cook, whisking along bottom of pot, until boiling, about 7 minutes. Reduce heat and gently simmer, stirring occasionally, until sauce is thickened, 10 to 12 minutes. Remove from heat and add 1 tablespoon butter, mustard, Old Bay, and cheeses. Stir until cheeses are melted and sauce is smooth; season with salt. Add macaroni to sauce and stir to combine.

In a large skillet, heat olive oil over medium. Add onion and cook, stirring occasionally, until softened, about 8 minutes. Add sausage and red-pepper flakes and cook, breaking up meat with a wooden spoon, until browned and cooked through, 8 minutes.

Add 4 cups prepared macaroni to skillet, gently stir to combine. Stir in cream and spinach, and cook until spinach begins to wilt, 4 minutes. To serve, sprinkle with shredded Parmesan.