Cook the spaghetti by bringing a large pot of salted water to a boil. Add the spaghetti and cook according to the package instructions until al dente, about 8–10 minutes. Reserve 1/2 cup of the pasta water before draining.

In a large skillet over medium heat, cook the thick-cut bacon slices until crispy and golden brown, about 5–7 minutes. Transfer to a plate lined with paper towels.

Leave about 1 tablespoon of bacon grease in the skillet. Sauté the sliced mushrooms for 5–7 minutes until browned and tender.

Stir in the minced garlic and cook for another minute. Then add in canned pumpkin puree, dried thyme, smoked paprika, nutmeg, salt, and pepper, mixing well.

Pour in the heavy cream and grated Parmesan cheese, stirring until blended. Continue cooking on low heat for 2–3 minutes to thicken the sauce.

Add the drained spaghetti into the skillet, tossing gently in the sauce until evenly coated. Use reserved pasta water if the sauce is too thick.

Serve in bowls topped with crispy bacon crumbles and garnish with fresh parsley and additional grated Parmesan.