Bring water to a rolling boil, add enough salt to make it taste like the sea, and add your dried pasta. Cook according to package directions; different kinds of pasta will have different cooking times. Once your pasta is al dente, strain through a colander.
To make the cashew cream, combine the cashews with ½ cup water in a high powered like a Vitamix. Blend until completely smooth. Note: if you don't have a high-powered blender, soak the cashews in warm water for at least 4 hours to soften them before blending them in a regular blender or food processor. Clean out the blender. Add the whole tomatoes and blend until they are puréed. Set aside.
To make the sauce, heat up the butter in a large skillet over medium heat. Add onions, garlic, and red pepper flakes and sauté for 2-3 minutes over medium heat until onions are translucent and fragrant. Add the puréed tomatoes, cashew cream, vodka, and salt and cook for another 7 minutes at a low simmer, stirring occasionally. Note: It's important to let the vodka cook down so that it removes the boozy flavor. Taste and adjust seasonings.
Stir in cooked pasta, vegan parmesan, and parsley. Serve with additional parmesan, parsley, and red pepper flakes.