*What is nutritional yeast?
It's yeast but it's not live like baker's yeast is, and they can't be substituted for each other. Nutritional yeast is grown specifically to be used as a food product but the yeast cells are deactivated (killed, essentially) during the manufacturing process. It's made to be added to foods to impart a cheesy, nutty, or savory taste. It's used in a lot of vegan foods to add extra protein, vitamins, minerals, and antioxidants, as well as a heap of umami flavor.