Step 1

Bring a large pot of water to a boil for the pasta. Salt the water and add the pasta. Cook until just shy of al dente. Drain, reserving 1 cup cooking water.

Step 2

Meanwhile, in a large skillet, melt butter over medium heat. Add evaporated milk and bring to a simmer. Whisk in pumpkin, mustard, and nutmeg. Add the cheeses and stir until melted. Season with salt.

Step 3

Add pasta to the sauce and stir until coated, adding some of the pasta cooking water if the sauce is too thick.

Step 4

Season to taste with salt and pepper, then serve immediately, topped with chives if desired.