Add cauliflower, onion, garlic, cashews, red peppers, and carrot to a pot of boiling water. Boil for 15-18 minutes until VERY tender. Cauliflower and carrot should be extremely soft.
Halfway through boiling veggies, begin cooking pasta. When pasta is aldente drain and set aside, reserving 1/2 C of pasta water.
Drain veggies/cashews and add to a blender with water and remaining ingredients except pasta and basil. Blend for 1-2 minutes until super smooth and creamy. Pour sauce into saucepan and cook over low heat to thicken and achieve a stretchier texture. Add pasta water as needed.
Add cooked pasta to saucepan and toss to coat and heat through. Serve hot with fresh cracked pepper and a sprinkle of fresh basil.