Bring a large pot of salted water to a boil. Add the shells and cook 1 minute less than package directions. Drain and set aside.
For the dairy-free Parmesan: In the bowl of a food processor, add the cashews, nutritional yeast, garlic powder and salt. Pulse until the consistency is a fine crumb. It will resemble freshly grated Parmesan.
For the vegan cheese sauce: In a large heavy-bottomed Dutch oven over medium heat, add the olive oil. Add the garlic and sweat for a minute or 2, until aromatic. Whisk in the flour until a sandy mixture forms. Slowly whisk in the cashew milk and allow the mixture to come to a simmer. Cook while whisking constantly until thickened, 3 minutes. Whisk in the Dairy-Free Parmesan and hot sauce and season with salt and pepper. Stir in the pasta and taste for seasoning. Serve.
The Dairy-Free Parmesan Cheese can be stored in the refrigerator for up to 1 week.