Drain the tofu from the package and wrap it with a cloth or paper towels. Give the tofu a gentle squeeze so that the cloth or paper towels absorb the extra moisture. Let the tofu sit on the counter for 10 to 15 minutes while you prepare the other ingredients.
Cut up the tofu into small, roughly 3/4-inch cubes. They don’t need to be perfectly uniform. Then, transfer the tofu cubes to a large bowl.
In a small bowl, mix the cornstarch and 1/4 teaspoon salt. Sprinkle half of the cornstarch mixture over the tofu and toss to coat. When you no longer see any dry cornstarch, sprinkle the remaining cornstarch mixture and toss again.
In another bowl, mix the remaining 1 teaspoon of salt, 1/2 teaspoon ground white pepper, and 3/4 teaspoon shiitake mushroom powder. Set it aside.
Pour the canola oil into a wok over medium-high heat. Once the temperature of the oil reaches 375ºF, the oil is hot enough for frying (it should take about 2 minutes). If you don’t have a thermometer, you can also test the temperature of the oil by pinching a tiny piece of tofu and carefully adding it to the wok. If the tofu sizzles rapidly, the oil is hot enough.
Fry the tofu in 3 or 4 batches. Carefully transfer 1/4 or 1/3 of the tofu into the wok. Don’t overcrowd the wok with tofu or else the tofu won’t fry properly. Fry the tofu for about 2 minutes, until the bottoms of the tofu start to brown. Using tongs, carefully flip the tofu over. Fry for another 2 minutes or so, until the tofu looks golden. Use a spider spatula to scoop up the fried tofu. Give the spatula a few shakes to shake out any excess oil. Transfer the fried tofu to the cooling rack. (See note 4 on how to keep tofu warm.)
Add another batch of tofu into the wok to fry. The tofu may brown more quickly than the first batch because oil is likely hotter now. You can reduce the heat to medium if you find the tofu is browning too quickly. Transfer the fried tofu to the cooling rack and repeat.
Once all the tofu cubes are fried, turn off the heat. Pour the hot oil into a heat-safe bowl, leaving about 2 teaspoons of oil in the wok. (See note 5 for information on what to do with the fried oil.)
Turn the heat to medium. Then, transfer the minced garlic to the wok and cook for 1 to 2 minutes, until most of the garlic is lightly golden. Turn off the heat and transfer the garlic to a bowl.
Heat the wok on medium. Pour 1 tablespoon of the oil that you used for frying tofu into the wok. Next, add the sliced red chili peppers, if using. Sauté the peppers for 1 to 2 minutes, until they start to soften. Then, add the scallions and sauté everything for another 10 to 15 seconds to soften the scallions. Transfer the peppers and scallions to the bowl with the garlic.
Add the fried tofu back to the wok. Sprinkle the salt and pepper seasoning over the tofu, and toss to coat the tofu with the spices. Taste a piece of tofu and add more salt, white pepper, or mushroom powder if necessary. Pour the garlic, peppers, and scallions over the tofu, saving some fried garlic to sprinkle over the tofu as garnish. Toss everything together.
Turn off the heat and transfer the tofu to a serving bowl. Sprinkle the remaining fried garlic over the tofu pieces. Serve the salt and pepper tofu immediately. This dish goes well with my jasmine rice
, egg fried rice
, kimchi fried rice
, Chinese garlic green beans
and/or Chinese garlic cucumber salad