Bring a large pot of salted water to a boil. Add the pasta and cook until al dente and drain, reserving 1 cup of the pasta water. Return the pasta to the pan.
Meanwhile, make the Smoky Cashew Cheddar Cheese by adding the soaked and drained cashews, filtered water, roasted red peppers, arrowroot, apple cider vinegar, smoked paprika, sea salt, black pepper, cayenne (if using), and hot sauce (if using) to a high-speed blender. Blend on high for 2 to 3 minutes or until completely smooth, stopping to scrape down the sides as needed.
Once the pasta is ready, pour the Smoky Cashew Cheddar Cheese mixture into a medium saucepan. Heat over medium for 5 minutes or until very thick and just shy of stretchy, whisking constantly. Once thickened, immediately turn off the heat to avoid overheating. Arrowroot loses its thickening power if overheated, so be attentive to it.
Spoon the cheese over the pasta and toss to coat, adding pasta water, a few tablespoons at a time, as needed to thin the sauce. Season with more sea salt, smoked paprika, and black pepper, to taste. I usually add another ½ teaspoon sea salt, another dash or two of smoked paprika, and a few grinds of black pepper; however, seasoning will vary depending on the amount of pasta you used and how salty your pasta water was, so adjust according to your tastes.