Cook the Pasta: Bring a large pot of salted water to a rolling boil, add pasta, and cook according to package directions until al dente, about 9-11 minutes. Reserve ¼ cup pasta water, then drain.

Brown the Sausage: In a large skillet over medium heat, add ground turkey sausage and cook for about 7 minutes, stirring in sage and garlic powder. Transfer to a plate, leaving drippings.

Sauté Aromatics: In the same skillet, add olive oil and butter over medium heat, then sauté minced garlic and chopped sage for 2-3 minutes.

Create the Roux: Sprinkle in flour, stirring for about 2 minutes until golden and thickened.

Whisk in the Milk: Gradually pour in milk, whisking to prevent lumps and cooking for 3-4 minutes until thickened.

Add the Pumpkin and Spinach: Stir in pumpkin puree and optional tomato paste, then add spinach and cook until wilted, about 2 minutes.

Combine Ingredients: Return sausage to skillet, stir in Parmesan, add drained pasta, and toss to coat. Use reserved pasta water to adjust consistency.

Serve and Garnish: Serve warm with extra Parmesan, nutmeg, and fresh sage for garnish.