Bring a large pot of salted water to a boil. Add the rigatoni and cook until al dente according to package instructions, usually about 10-12 minutes. Drain the cooked pasta and set aside.

In a large skillet, melt the butter over medium heat. Add the finely diced onion and sauté for about 3 minutes, then add the minced garlic. Continue to cook, stirring, until both are soft and fragrant, about 2 more minutes.

Whisk the pureed pumpkin, chicken broth, heavy cream, sour cream, ground nutmeg, salt, and black pepper into the softened onion and garlic mixture in the skillet. Stir well to combine. Bring the sauce to a gentle simmer and cook for 10 minutes, stirring occasionally so it doesn’t stick. I like to taste and adjust seasoning at this stage—try adding a little extra nutmeg if you love warm flavors.

Add the cooked rigatoni (from Step 1) into the skillet with the simmering pumpkin sauce. Gently toss or stir to fully coat the pasta. Let everything simmer together for 2-3 minutes until the sauce thickens slightly and the pasta is heated through.

Serve the pasta hot, garnishing each portion with grated Parmesan cheese and fresh chopped parsley. For extra richness, I sometimes add a little more Parmesan on top, right before eating.