01 - Cut the tofu into 1-inch cubes. Dissolve 1 teaspoon salt in 2 cups water and soak tofu cubes for 10 minutes to season. Drain thoroughly and pat dry with paper towels.
02 - In a mixing bowl, combine rice flour, cornstarch, white pepper, garlic powder, turmeric powder if using, and 1/2 teaspoon salt. Gradually whisk in 1/2 cup cold water until smooth and thin.
03 - Pour enough vegetable oil into a deep pan or wok to reach 2 inches depth. Heat to 340°F over medium-high heat.
04 - Dip each tofu cube into the batter, allowing excess to drip off. Carefully lower into hot oil and fry in batches, turning occasionally, until golden brown and crisp, about 5-7 minutes per batch.
05 - Remove fried tofu with a slotted spoon and drain on paper towels. Serve immediately with fresh chilies and sweet soy sauce if desired.