Soak the cashews in water overnight or in boiling water for 20 minutes.
Preheat oven to 350. In a medium saucepan, bring water to a boil and then add in the pasta. Cook for about 15 minutes or until soft.
Chop the red pepper and half of the onion. Add to a baking tray with a little bit of olive oil and bake for about 20 minutes or until slightly crispy.
Once the pepper and onion are finished baking, add them to a blender. Then add the rest of the onion, garlic, cashews, tomato paste, nutritional yeast, tomato paste, milk, salt, and pepper to the blender.
Blend everything together until creamy. Then add the sauce to the pasta and serve. Top with red pepper flakes to taste.