Begin by soaking cashews in hot water for 10 minutes
While cashews are soaking, bring a large pot of salted water to a boil. Boil onion and butternut squash for 10 minutes, until tender. Use a slotted spoon and add squash and onion to a high speed blender.
Bring water back to a boil and cook pasta according to package instrustions.
Drain the cashews and add to blender. Place the rest of the ingredients in the blender (not the pasta). Blend until creamy.
Once the pasta is done cooking, drain and place back in the pot. Stir through the 'cheese' sauce. Serve and enjoy!