Nutritional yeast is a deactivated yeast product that is commonly used as a cheese substitute by vegans and those with dairy allergies. It has a nutty and cheesy flavor that can be added to a variety of dishes, including popcorn, sauces, dressings, pasta dishes, and vegetables. Nutritional yeast is a good source of vitamin B and can be used to add a savory, umami taste to meals. It is available at Trader Joe's and can be found in the baking or seasoning aisle.