Tofu is a popular stir-fry ingredient, made from soybeans that have been pressed into a solid block. It is a versatile ingredient that can be used in a variety of dishes, including stir-fries. It is high in protein and low in fat, making it a healthy choice for those looking to add more plant-based proteins to their diet. Tofu is also a great source of calcium, iron, and other essential vitamins and minerals.