1.Line a large baking sheet with parchment paper and place a rack on top. Set aside.
2.Combine the panko and oil in a frying pan and toast over medium heat until golden brown. Transfer panko into a shallow dish and allow to cool.
3.Butterfly the chicken breast and cut in half. Using a mallet, pound the chicken to equal thickness, if necessary. Season on both sides of the chicken with salt, pepper, and garlic powder.
4.In a shallow dish, add flour and in another shallow dish, whisk together the egg and water. Preheat oven to 400 degrees.
5.Coat each chicken piece in the flour and shake off any excess flour. Dip into the egg mixture and then coat with the toasted panko, pressing firmly to adhere to the chicken.
6.Place the chicken pieces on the prepared baking sheet and bake until the chicken is no longer pink inside, about 25-30 minutes. Let chicken cool for 10 minutes on rack. Slice each piece with one downward motion and serve immediately.