Gently squeeze the tofu to remove excess liquid, then use your hands to break it into craggily bite-sized pieces. Set aside. Combine the soy sauce, brown sugar, white pepper, and ¼ cup of water in a jar, whisk, and set aside.
Heat enough oil to cover the bottom of a large skillet. Toss the tofu pieces in cornstarch and then transfer to the hot oil in a single layer, working in batches if needed. Fry until crispy and golden, then flip to the other side and continue until all the tofu is crispy. Remove fried tofu from the pan to a clean plate, sprinkle with salt, and set aside. Repeat with any remaining tofu.
Add a little more oil to the pan if needed, and then add the garlic and chili peppers to your skillet. Cook, stirring, until the garlic is fragrant. Add the mixed sauce and cook, stirring, for just a couple minutes, until it starts to thicken. Add the tofu back to the skillet, stir to coat in the sauce, and turn off the heat. Top with the chopped scallion, and enjoy.
