Add the pasta to a pot & cook according to instructions, then drain.
While the pasta is cooking, in another pot cover the butternut squash with boiling water and cook on medium to high till soft ~ 10 mins, then drain reserving 1/2 cup of liquid for the sauce.
While the squash and pasta are cooking soak the cashews in boiling water to soften for 10mins then drain.
Add all the ingredients (except for the pasta) to a blender and blend till smooth.
Pour the sauce over the cooked pasta and serve.