Fill a large pot with water, add a pinch of salt, and bring it to a boil. Add the fettuccine pasta and cook according to package instructions until al dente, about 10-12 minutes. Stir occasionally to prevent sticking. Reserve 1/2 cup pasta water, then drain pasta and set aside.
While the pasta cooks, heat 2 tablespoons olive oil in a large skillet over medium heat. Add minced garlic and sauté 1-2 minutes until fragrant but not browned.
Reduce heat to low and stir in 1 cup pumpkin puree and 1 cup heavy cream. Mix until smooth and warm through. Add nutmeg, salt, and black pepper; stir to combine.
Slowly sprinkle in 1/2 cup grated Parmesan cheese, stirring continuously until melted. If sauce is too thick, add reserved pasta water to loosen to desired consistency.
Add drained fettuccine to skillet with pumpkin Alfredo sauce. Toss gently to coat pasta thoroughly. Cook together on low heat 1-2 minutes to absorb flavors.
Remove from heat, sprinkle chopped fresh parsley on top, and toss lightly. If using, sprinkle cooked and crumbled turkey bacon over the dish. Serve immediately warm and creamy.
