Cut the tofu into large cubes (about 1-inch), about 32 cubes per package. Lay the cubes on a paper towel and let them dry a bit. Toss them in the cornstarch, shaking off excess.
400 grams tofu, ½ cup corn starch
Heat a large fry pan. Heat half the oil until the oil is shimmering. Add half the tofu to the pan. Let it cook undisturbed until the first side is golden brown, then flip, brown second side, and repeat until most sides are brown. Remove from pan to a plate. Add the rest of the oil and remainder of the tofu and repeat with second batch, remove.
3 tbsp canola oil
Add garlic and ginger to the pan and cook until fragrant, less than one minute. Sprinkle brown sugar into the pan, toss quickly for 30 seconds or so. Add the tamari and mirin, allow to bubble and reduce for a minute.
3 cloves garlic, 1½ tsp ginger, 2 tsp brown sugar, 3 tbsp tamari, 1½ tbsp mirin
Add back the tofu cubes and carefully toss with liquid in the pan. Shut the heat off and continue tossing until well coated.
Sprinkle with green onion, chilies and pepper.
2 stalks green onion, 1 red chili pepper, 1½ tsp pepper