In a saucepan, bring water to a boil. Add in penne and boil until cooked.
At the same time, heat olive oil in a pan and add chopped onion.
Soak the cashews in hot water for 15-20 minutes or until soft.
Add cashews and the rest of the cheese sauce ingredients into a blender and mix until smooth and creamy.
Drain the noodles and combine in a pan with spinach, salt and pepper and sauce.
Cook for about 5 minutes on medium.
Add additional pasta water to make it creamy.
Serve in a pasta bowl and enjoy!