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