Place the cashews, nutritional yeast, lemon juice, garlic powder, salt, and pepper in a food processor. Pulse repeatedly to break the cashews down, until they form a coarse, wet meal. Scrape the sides of the food processor down with a spatula.
Turn the motor of the processor on. With the motor running, drizzle in the water and let the cashews process for about 10 seconds. Stop and scrape the machine down again. Continue processing for a full 1-2 minutes, or until the cashew cheese is smooth and thick, adding a tablespoon of extra water if needed. The consistency should be a little bit like hummus (see photos of finished cashew cheese as a cue).
Taste the cashew cheese and add lemon, salt, and pepper to taste. If you like, pulse in fresh herbs or other flavorings. Serve. Cashew cheese will keep for up to 6 days in an airtight container in the fridge.