In a high speed blender combine cashews, nutritional yeast, onion powder, garlic powder, salt, cornstarch, bell peppers and approximately one cup of the water. You want just enough water to get the mixture to blend into a slurry, but not so much water that the mix is loose. If the mix is too watery, it won't blend as smoothly and the nacho cheese sauce will be chunky.
In a medium saucepan, bring the remaining water (approximately 3 cups) to a boil. Whisk in the blended slurry, stirring constantly. Once thick, off heat and whisk in the lemon juice
Notes
This recipe makes A LOT. It reheats well, but will firm up in the fridge, so just add water to pan and whisk in the set up cheese while heating and all will be well