01 - Cut the chicken breasts into thin strips, about 1/2 x 2 inches. Pat dry with paper towels and season evenly with salt and pepper.
02 - In a mixing bowl, whisk together the all-purpose flour, cornstarch, and baking powder until well combined.
03 - In a separate bowl, lightly beat the egg, then mix it with the ice-cold sparkling water.
04 - Pour the wet mixture into the dry ingredients. Stir very briefly with chopsticks or a fork, leaving the batter slightly lumpy—do not overmix to maintain light texture.
05 - Heat the vegetable oil in a deep pan or fryer to 350°F.
06 - Dip the seasoned chicken strips into the batter, allowing excess to drip off.
07 - Carefully add the battered chicken to the hot oil. Fry in batches for 3–4 minutes until golden and crisp, turning once. Do not overcrowd the pan to ensure proper frying.
08 - Transfer cooked chicken to a wire rack or paper towels to drain excess oil.
09 - Combine soy sauce, mirin, rice vinegar, sugar, and ginger in a small saucepan. Heat gently until sugar dissolves, then cool to room temperature.
10 - Serve the chicken tempura hot with the dipping sauce on the side. For a complete meal, pair with steamed rice and pickled vegetables.