Preheat the oven to 400°F.
Prepare the mac 'n cheese of your choice and set aside.
Boil the cashews for the ricotta for 15 minutes. While boiling, add all of the other ingredients except for the tofu to a blender.
Once the cashews are done, add them to the blender and blend until smooth. Add salt and pepper to taste.
Using a fork, mash the tofu so that it is crumbly in a large bowl. There should be no large pieces.
Add the cashew mixture to the tofu and mix well. Set aside.
Add all of the ingredients for the homemade parmesan to a food processor and pulse until crumbly and no large pieces of cashews remain.
To assemble the lasagna, spread the cheese sauce on the base of the casserole dish. Then, layer mac 'n cheese, ricotta cheese, spinach, ricotta, and finally mac 'n cheese. Sprinkle parmesan cheese at least on top of the casserole, but you can also sprinkle judiciously throughout.
Place the lasagna in the top third of the oven for 25 minutes. When done, you'll hear and see a bit of bubbling underneath the top layer of mac 'n cheese. Let cool for 20-25 minutes before eating (the longer it cools, the more distinct the layers will be).