Place cashews in a heatproof bowl and cover with boiling water. Let soak for 15-20 minutes, until very soft. Drain and rinse the cashews and set aside.
Meanwhile, bring a large pot of water to a boil and generously salt. Add the pasta, stir, and cook according to package instructions. Reserve 1 cup (240 ml) of pasta water (amount as original recipe is written // adjust if altering batch size), then drain and return the noodles to the pot, off of the heat.
After soaking, transfer the cashews to a high-speed blender. Add the lemon juice, nutritional yeast, garlic, turmeric, chili powder, salt, pepper, and 1/2 cup (120 ml // amount as recipe is written // adjust if altering batch size) reserved pasta water. Blend until smooth. Add more pasta water if necessary to reach your desired consistency. Taste and adjust seasonings if needed, adding nutritional yeast for cheesiness, lemon juice for acidity/brightness, turmeric for more vibrant color, and salt to taste. It should be very flavorful!
Pour the cheese sauce over the pasta and toss to coat. Add more pasta water as needed to coat the noodles.
Serve immediately as is or garnish with vegan parmesan cheese (optional). Leftovers will keep in a sealed container up to 3-4 days. Reheat leftovers in the microwave or on the stovetop over medium-low heat until hot, adding a little plain unsweetened dairy-free milk (almond typically works best) to rehydrate as needed. Not freezer friendly.
*Nutrition information is a rough estimate calculated with Banza GF chickpea shells and without optional ingredients.