Melt the butter and add the roasted cashews. Allow to soak while you prepare the remaining ingredients.
In a large sauce pot bring the water to boil, add the sushi rice, and once it returns to a boil reduce heat to medium. Cook uncovered for 10 minutes. Add the garlic and cook for 5 minutes.
Transfer rice and water to a blender and add in the nutritional yeast, miso, lemon juice, salt, and the butter soaked cashews. Blend until smooth. Leave the sauce in the blender until your pasta is finished cooking. Add more water if it's too thick. It should be on the thinner side because gloopy alfredo is gross.
Cook your noodles in salted water. It makes a huge difference because the noodles are salted from the inside out rather than just flavored with salt. Once your noodles are cooked to al dente reserve 1/4 cup of the water. The starchy and salted water adds flavor as well as a sheen to the sauce. You should always do that when making pasta sauce.
After draining the noodles, return them to the pot and pour in the alfredo sauce. Gently turn the noodles to mix and allow to rest in the sauce for 5 minutes before serving. Top with fresh cracked pepper and enjoy!