Place the potatoes, cauliflower, onion, cashews, salt and water in a large pot, cover with a lid and cook over medium heat for 20 minutes.
After 20 minutes, turn off the heat and transfer everything in the pot (including the remaining liquid) to your blender. Blend until creamy and smooth. You may have to do this in batches depending on the size of your blender.
Consider this sauce your starting point. From here you can do whatever the hell you want with it. Make scalloped potatoes, mac and cheese with broccoli, put it in enchiladas, pour it over a burrito, use it for a lasagna, whatevs. I’m going the green chili mac and cheese route.
Cook your pasta (I like brown rice spirals) as per the directions on the box and then strain the water and place the pasta back in the pot.
Add as much Sauce as you like, along with the green chili and stir.