Heat a large skillet or pot over medium heat. Cook ground beef until no longer pink (or diced up pancetta until slightly crispy). Add garlic and sauté for 2 more minutes. Turn heat off.
Boil spaghetti in a separate pot until it is al dente. Drain but reserve some of the pasta water for the sauce.
In a bowl, mix pumpkin puree, 2/3 of the Parmesan, salt, nutmeg, and egg yolks. Slowly whisk in a bit of reserved pasta water until smooth and slightly thick.
Add al dente spaghetti noodles to the ground beef skillet. Add pumpkin mixture and gently toss over low heat for 2–3 minutes, adding more pasta water if needed to reach a creamy consistency.
Serve immediately, topped with remaining Parmesan, fresh thyme, or other garnishes as desired
Notes
Pumpkin Spaghetti with Jar Spaghetti Sauce
If you want to make this with a jar of spaghetti sauce choose a regular marinara type of sauce. Add 1/2 cup to 1 cup of pumpkin puree (not pumpkin pie filling). Start with 1/2 cup, stir in with a pinch of nutmeg and salt and taste. If you want a stronger pumpkin flavor add in more puree until it is just right for you. Heat, combine with cooked noodles and enjoy.