01 - Cut the tofu into 1-inch cubes. Dissolve 1 tsp salt in 2 cups water and soak tofu cubes for 10 minutes to season. Drain and pat dry thoroughly with paper towels.
02 - In a bowl, combine rice flour, cornstarch, white pepper, garlic powder, turmeric powder (if using), and 1/2 tsp salt. Gradually add 1/2 cup cold water, whisking to form a smooth, thin batter.
03 - Heat enough vegetable oil in a deep pan or wok to 340°F.
04 - Dip each tofu cube in the batter, letting excess drip off, then carefully lower into the hot oil. Fry in batches, turning occasionally, until golden brown and crisp (about 5-7 minutes per batch).
05 - Remove with a slotted spoon and drain on paper towels. Serve hot with fresh chilies and sweet soy sauce, if desired.