Bring a large pot of salted water to a boil, over high heat. Cook the macaroni according to package instructions. Drain and reserve.

While the water boils, work on the sauce.

In a saucepan, over medium heat, melt the butter. Once the butter is melted, whisk in the flour and cook for about a minute to get rid of the raw flour taste, being careful not to burn.

Add the milk slowly, whisking constantly until the sauce thickens and there are no more lumps, about 3 minutes.

Add the pumpkin and the cheese and stir until the cheese melts and you have a nice, rich and creamy orange sauce. Add the dry mustard, the nutmeg and season with salt and pepper to taste.

Add 1/2 of the pumpkin cheese sauce to the pats and stir until it coats the pasta evenly. Then add the remaining sauce and stir to combine.

Serve immediately while hot!