Cook pasta according to package directions (I recommend cooking 1-2 minutes less than the box time so it's slightly al dente). Reserve 1/2 cup of pasta water, then drain the pasta and set aside.
Deglaze the pan with the vodka, making sure to scrape up any browned bits on the bottom of the pan.
Stir in the pumpkin puree and cook for about 1 minute.
Add in the heavy cream, sage, salt, pepper, and nutmeg then reduce the heat to low.
Stir occasionally and continue to cook until the sauce begins to simmer and thickens slightly. Taste and adjust seasonings if needed.
Add the al dente pasta to the sauce and toss gently to combine for 1-2 minutes or until the sauce thickens up and coats the noodles. If needed add in a small amount of reserved pasta water at a time to loosen the sauce (I usually use about 1/4 of a cup).
Remove from the heat and serve immediately.
To make crispy sage leaves: Add 1 tablespoon of butter to a non-stick pan and heat gently over medium heat. Add a handful of sage leaves and watch closely for them to crisp up (1-2 minutes). Remove and set aside.
Garnish pumpkin pasta with parmesan cheese and crispy sage if desired.