Firm tofu gets coated in cornstarch then pan-seared until browned on both sides. The sweet and sour sauce is added to the seared tofu and as it sizzles in the hot pan, creating a thick, glossy glaze that adheres to the tofu. This is a fast and easy way to make intensely flavorful tofu. If you use tamari instead of soy sauce, this dish is 100% gluten-free.