Bring a large pot of salted water to the boil; when that happens, you'll want to add the pasta in and cook it according to the instructions on the package.
In the meantime, bring 3-4 cups of water to the boil in a pot that you can use a steamer with. Reserve 1 cup of this boiling water and then steam the cauliflower florets until they are tender, about 6-8 minutes.
Meanwhile, add the reserved cup of boiling water, raw cashews and garlic cloves to the container of a high-speed blender and process on high speed until super smooth and creamy, scraping the sides as needed.
When the cauliflower is fully cooked, carefully add it to the blender, along with the vegan parmesan, lemon juice, salt and white pepper. Process on high again until the sauce is super smooth and silky. Set aside.
As soon as the pasta is cooked to your liking, drain and return it to the pot. Add the sauce to the pot and stir delicately until the pasta is completely and evenly covered in sauce.
Serve without delay, garnished with a little bit of chopped parsley and more of that delicious vegan parmesan.