Place the cauliflower, onion and garlic (smashed but not chopped) in a small pot, cover with water and bring to a boil. Cook until the cauliflower is tender.
Transfer the veggies in the blender together with the drained cashews, the seasonings and 3/4 cup of the cooking water. Process until nice and smooth.
Taste and adjust the seasonings and liquids if necessary. Serve on warm pasta and top with nut parmesan.
You can either cook your pasta -in separate pot- at the same time as the veggies or use the leftover cooking water (+ extra as needed) to cook them while you process the sauce. Add your zoodles to the pot 2-3 min. before the spaghetti is done.
Yields around 4 portions. You can keep leftover sauce in the fridge. It goes great on pizza!
If you don't have time to soak the cashews, cover them with boiling water and let sit for 10-20 min.