The main ingredient in tofu is soybeans. Specifically, it is made by coagulating soy milk, which is derived from ground soybeans, and then pressing the resulting curds into solid blocks. Tofu is a staple in many Asian cuisines and is particularly popular in vegetarian and vegan diets due to its high protein content and versatility. It comes in various textures, including silken, soft, firm, and extra firm, making it suitable for a wide range of dishes, from stir-fries to soups and desserts.