Soak the raw cashews in water for a minimum of 2 hours. Drain and rinse them thoroughly.

In a large pot, heat the olive oil over medium heat. Add the chopped yellow onion and sauté until translucent, about 4-5 minutes.

Introduce the minced garlic to your pot and sauté for an additional minute.

Add the tomato paste and mix well, cooking for a couple of minutes.

Pour in the can of diced tomatoes and their juice. Add the crushed red pepper flakes and the ¼ teaspoon of salt. Stir and let it simmer for about 10 minutes.

In a blender, combine the soaked cashews with ½ cup of fresh water and ½ teaspoon of salt. Blend until completely smooth.

Stir the cashew cream into the tomato mixture and heat for an additional 2-3 minutes.

In a separate pot, bring salted water to a boil and cook the rigatoni according to package instructions.

Add the drained rigatoni into the creamy tomato mixture, tossing to combine. If the sauce is too thick, add reserved pasta water to reach desired consistency.

Taste and adjust the seasoning before serving, garnishing with fresh herbs or nutritional yeast if desired.