Fill a large pot with salted water and bring it to a boil. Add spaghetti and cook until al dente, about 8-10 minutes. Reserve ½ cup pasta water before draining.

In a large skillet, heat thick-cut bacon over medium flame for 5-7 minutes until crispy. Transfer to a paper towel to drain and crumble.

Leave 1 tablespoon of bacon grease in the skillet. Sauté sliced mushrooms over medium heat for 5-7 minutes until browned.

Stir minced garlic into the skillet with mushrooms and cook for an additional minute until fragrant.

Add pumpkin puree, thyme, paprika, nutmeg, salt, and pepper to the skillet. Stir well and heat for 2-3 minutes.

Pour in heavy cream and add grated Parmesan cheese. Stir over low heat for 2-3 minutes until thickened.

Combine drained spaghetti into the skillet, gently tossing to coat. Add reserved pasta water if needed for consistency.

Serve the spaghetti in bowls topped with crumbled bacon and parsley. Optionally, add more Parmesan on top.