Start by bringing a large pot of salted water to a boil. Once boiling, add the elbow macaroni and cook according to the package directions, aiming for al dente. This usually takes about eight to ten minutes. Once cooked, drain well, but do not rinse the pasta. Rinsing can remove the starch that helps the sauce adhere to the noodles.
While the pasta is cooking, in a large saucepan over medium heat, melt the unsalted butter. As it melts, use a whisk to stir in the all-purpose flour. Cook for one to two minutes until the mixture is bubbly and golden. This is your roux, and it’s essential for thickening the sauce.
Next, gradually add the milk, followed by the heavy cream and chicken broth, a little at a time. Continuously whisk until each addition is smooth before adding more. This will help prevent lumps and ensure a silky sauce.
Once all the liquids are added and the mixture is smooth, stir in the dry mustard, nutmeg, cinnamon, salt, ground black pepper, onion powder, garlic powder, and pumpkin puree. Cook over medium heat, stirring regularly until the mixture comes to a gentle boil. You’ll notice the color deepening and the flavors developing beautifully.
Once boiling, allow it to boil for one minute while whisking. Remove from heat and immediately stir in the sharp cheddar cheese and parmesan cheese. Stir until the cheese is entirely melted and the sauce is smooth.
Now, gently fold in the cooked pasta until it's well coated with the cheesy pumpkin sauce. If the sauce seems too thick, you can add a splash of reserved pasta water to loosen it up.
Once everything is combined, taste it! This is the perfect moment to adjust the seasoning. Add more salt or a dash of hot sauce if desired.
Serve immediately for the creamiest texture. You can garnish with additional cheese or herbs if you’d like, but it’s absolutely delicious as is.
