Bring 2 cups of water to a boil (I use my electric kettle.) Pour the hot water over the cashews and let soak for 5 minutes, then drain the cashews and discard the soaking water. Set aside.
Get out a clean container that can hold about 3 cups. I prefer glass, but plastic will work. Have it ready before you start because you will need to move quickly once the cheese is blended.
Heat up the 1 1/2 cups of water. It will need to be boiling when you add it to the blender. Again, I heat up water in my tea kettle, then measure 1 1/2 cups when I'm ready. You can also simply get it boiling in a small pan on the stovetop.
To a high powered blender (if you use tofu instead you can use a regular blender), add the soaked and drained cashews, tapioca starch, kappa carrageenan, nutritional yeast, salt, coconut oil, lemon juice and apple cider vinegar.
CAREFULLY pour in the boiling hot water, and immediately put the lid on and blend. Use a towel for extra protection so the hot water does not burn you! Blend until smooth, stopping to scrape down once if needed. It will only take a minute or so, and the mixture will start to harden fast so you need to work quickly.
Immediately pour the cheese into your prepared container. It will start to harden super fast, so do not wait.
Move the container to the refrigerator, uncovered and let chill for 1-2 hours, until solid throughout and cooled.
After a few hours, pop it out of the container, and either slice/shred right away or wrap in paper towels, then place in a large ziplock bag or container. This will help it be drier, which I think makes it better.
Use anywhere you would real mozzarella, such as on pizza, grilled cheese, cold sandwiches, pasta dishes, Mexican dishes, on top of soups or just for snacking.