Slice the chicken breast thinly and season with salt and pepper.
Mix potato starch and egg whites to make a batter.
Coat the prepared chicken breast with the batter.
Heat a generous amount of cooking oil in a pan and fry the chicken breast until golden brown.
Drain the oil from the fried chicken breast and let it cool briefly in the pan.
In a pan, combine vinegar, sugar, soy sauce, and ketchup to make the sauce.
Lightly toss the fried chicken breast in the sauce.
Nicely plate the dish for serving.