In a medium pot, combine the cashews, potatoes, nutritional yeast, garlic, almond milk, salt, and black pepper. Bring to a boil over medium-high heat, and simmer for about 10 minutes, until you can pierce a fork through the potatoes.
Transfer the cashew mixture into a blender, add the miso and 1 cup water, and blend until smooth. Set it aside.
In a large, deep skillet, bring 3 ½ cups water to a boil over high heat. As soon as it comes up to a boil, add the pasta and cook for 3 minutes, stirring occasionally so that the noodles don't stick to each other.
Then, pour in the cashew mixture, gently pushing the pasta down to fully submerge it in the creamy liquid.
Reduce the heat to medium heat and gently cook, stirring frequently, until the pasta is cooked through, about 15 minutes. The sauce will thicken—add more water ¼ cup at a time if it thickens too quickly and it looks dry.
If the sauce starts sticking to the bottom of the skillet, reduce the heat to low and add a couple tablespoons of water as you stir the pasta.
Taste and season with more salt and black pepper.
Top with parsley and serve.
