Bring a large pot of salted water to a boil. Throw in the pasta and cook according to package directions. Reserve at least 1/2 cup of pasta water and then drain.
In a saucepan, add the butter and olive oil over medium heat. Allow the butter to toast and brown and then add the garlic and tomato paste. Cook for about 4 to 5 minutes. The tomato paste will darken in color from a bright red to reddish brown.
Add the pumpkin puree and mix together. Cook down the pumpkin puree for 2 to 3 minutes.
Add the heavy cream and mix until incorporated. Simmer for about 2 to 3 minutes.
Add the reserved pasta water and whisk together to thin out the sauce.
Finally, add the grated parmesan, sage, red pepper flakes, paprika, nutmeg, onion powder, salt, and black pepper. Mix into the sauce, taste, and adjust anything to your taste.
Toss in the cooked pasta and mix to coat evenly.
Serve with more parmesan on top!