Prepare pasta according to package directions. Drain and return pasta to the cooking pot; set aside.
To a small saucepan over high heat, add cashews and enough water to cover by 1 inch. Bring to a boil for 8 minutes. Drain and set aside.
To a medium size pot over high heat, add butternut squash, onion, and enough water to cover by 1 inch. Bring to a boil then reduce heat to low; simmer 15 minutes, until squash is fork tender. Use a measuring cup to scoop out 1/4 cup of the cooking water; set aside. Drain squash and onions.
To a high speed blender, add cashews, squash & onion mixture, lemon juice, salt, mustard, garlic powder, black pepper, smoked paprika, turmeric, nutmeg, and reserved cooking liquid. Blend on high 1 minute, or until completely smooth.
To the prepared pasta, add all of the butternut sauce and Parmesan cheese, Stir gently to coat the noodles. Serve hot.