Start by chopping your chicken breast into bite-sized pieces. This allows the batter to coat all sides evenly. Season the chicken with light soy sauce, white pepper, kosher salt, cornstarch, and garlic powder. Mix well and let it marinate for about 15 minutes.
In a bowl, combine all the batter ingredients: flour, cornstarch, egg, water, baking powder, and baking soda. Whisk until smooth. The batter should be thick enough to coat the chicken but not so thick that it wouldn’t stick.
In a large frying pan or wok, pour in vegetable oil until it’s about 1-2 inches deep. Heat the oil over medium-high heat until it reaches 350°F (175°C). You can test if the oil is ready by dropping a small amount of batter into it; it should sizzle immediately.
Dip each marinated chicken piece into the batter, ensuring it’s fully coated. Carefully place them in the hot oil. Fry in batches to avoid overcrowding the pan. Cook the chicken for 3-5 minutes until golden brown and crispy. Transfer the cooked chicken to a paper towel-lined plate to absorb any excess oil.
In a saucepan, combine sake, honey, rice vinegar, soy sauce, granulated sugar, cornstarch, water, and sesame oil. Stir over medium heat until the sauce has thickened, which should take just a few minutes. Make sure to keep stirring to prevent any sticking.
Once the sauce is ready, pour it over the fried chicken pieces in a large bowl. Toss gently to ensure every piece is evenly coated.
Transfer the glazed chicken to a serving plate. Finally, garnish with chopped green onions for a fresh touch.