Add butternut squash, onions and cashews to a pot and cover with water by at least an inch or two. Bring to a boil, turn down heat to medium and simmer until vegetables are tender (about 15 minutes or so).
Meanwhile, cook macaroni noodles according to package directions. Reserve ½ cup cooking liquid once noodles are done cooking and before draining. Place noodles back in pot and set aside.
When squash and onions are tender, drain and add them to a high speed blender with the cashews, lemon juice, salt, dijon, garlic powder, black pepper, smoked paprika, turmeric, nutmeg and reserved cooking liquid from the noodles. Blend until completely smooth. Use a tamper if necessary to push ingredients to the bottom of the blender.
Add butternut squash sauce to the macaroni noodles and stir, making sure every noodle is covered in sauce. Warm through if needed.