Prepare the Sauce: In a medium bowl, combine chicken broth, lemon juice, rice vinegar, Shaoxing wine (if using), sugar, cornstarch, lemon zest, and salt until fully mixed. Set aside.

Marinate the Chicken: Cut chicken breast into bite-sized pieces. Mix with vegetable oil and 1/2 tsp salt, ensuring all pieces are coated. Let it sit for 15 minutes.

Coat the Chicken: Beat one egg in a small bowl, add to chicken, and mix to coat. Sprinkle cornstarch over chicken and toss to coat well.

Cook the Chicken: Heat 1/3 cup vegetable oil in a large skillet over medium-high heat. Add coated chicken in a single layer and cook for 2-3 minutes until golden brown. Flip and cook for another 2-3 minutes.

Cool the Chicken: Transfer chicken to a plate, allowing to cool for 2-3 minutes to maintain crispiness.

Sauté Aromatics: In the same skillet, add white parts of green onions and minced ginger. Sauté for 1-2 minutes until fragrant.

Thicken the Sauce: Pour the prepared sauce into the skillet with aromatics. Increase heat and cook for 2-3 minutes, stirring until the sauce thickens.

Combine Chicken and Sauce: Add crispy chicken back to the skillet and toss in the thickened sauce. Cook for an additional minute.