Cut the chicken breast into uniform bite-sized pieces and season with salt and white pepper. Let it rest for 10 minutes.

In a mixing bowl, combine all-purpose flour, cornstarch, garlic powder, white pepper, salt, and chicken stock powder. Whisk until blended.

Mix 1/4 cup of the dry mixture with 2 tablespoons of water to form a thick batter, then coat the chicken pieces thoroughly.

Dredge each batter-coated chicken piece in the reserved dry mix, ensuring even coating.

Heat enough cooking oil in a frying pan to about 1 inch deep over medium heat.

Fry chicken pieces for 3-5 minutes on each side until golden brown and crispy.

Transfer fried chicken to a cooling rack over a baking sheet to drain excess oil.

Whisk together gochujang paste, ketchup, and sesame oil in a bowl to make the sauce.

Toss the cooked chicken in gochujang sauce until evenly coated.

Plate the chicken and sprinkle with sesame seeds. Serve immediately.