All you need in order to make this dreamily creamy and cheesy vegan pasta dish is a decent blender, a cast-iron pan, and some umami-inducing pastes and spices. Atop the mac is a crispy, crunchy broiled breadcrumb crust, a compliment to the cashew cheese'd pasta beneath, which is flavored with smokey chipotle peppers.
Begin by soaking 1 cup of raw cashews in hot water for about 30 minutes. Meanwhile, in a cast-iron skillet, sauté the yellow onion and garlic for about 7 - 9 minutes, until they become more translucent and start to brown. Then, drain the cashews and add them to a blender, along with the sautéed onion and garlic, vegetable broth, nutritional yeast, lemon juice, white miso paste, dijon mustard, ground turmeric, chipotle pepper (add 3 for a more spicy sauce), and dash of salt. Blend this until it's very smooth.
While this is happening, cook your pasta in a couple quarts of salted boiling water until tender. You'll need about 4 cups of cooked pasta, which is probably about half as much when dry. The cook time depends on the pasta you're using - you can use pretty much whatever, but I'd recommend classic macaroni noodles or some kind of penne. Drain the pasta well, and then set it aside until you're ready to use it.
Now, add the blended cheese sauce to the cast-iron pan (that you cooked the onion and garlic in) over low-medium heat, and let it thicken for about 5 minutes, stirring frequently. Then, add the 4 cups of cooked pasta, and stir to incorporate and heat through, another 2 - 3 minutes or so.
Lastly, in a small bowl, combine together the breadcrumb topping ingredients. Sprinkle the breadcrumbs over the top of the macaroni in the cast-iron, and then place the cast-iron about 6 - 10 inches away from the broilers in your oven, and broil for 2 minutes or so, until the breadcrumbs become brown and toasty. Watch it - this happens quickly. After that, it's ready to serve!