Slice the chicken breast into about ½-inch thick pieces, then cut into ½-inch wide strips, and trim any long strips into 2-inch pinky-sized pieces.
2
Combine the white pepper, five-spice powder, garlic salt, salt, sugar, chicken bouillon, cornstarch, and water with the chicken, then massage by hand so the marinade is fully absorbed.
3
Crack an egg and separate the yolk from the white. Set the yolk aside and mix it into the chicken only right before frying, to keep it from drying out too soon.
4
In a separate bowl, mix together the salt, garlic salt, five-spice powder, and white pepper to make the seasoning powder.
5
Just before frying, mix the egg yolk into the marinated chicken, then add the dry flour and hand-toss for about a minute until every piece is evenly coated.
6
Fill a pot or wok about halfway with oil and heat over high heat to around 350°F (176°C).
7
Fry the chicken in two batches, adding pieces one by one to prevent sticking, and cook each batch for 2-3 minutes until golden and crispy, then remove with a strainer.
8
Raise the oil temperature to about 380-390°F and re-fry each batch for roughly 30 seconds until the chicken turns a deeper golden brown.
9
Transfer the fried chicken to a clean bowl. Pour the seasoning powder into your hand and sprinkle it in gradually while tossing the bowl, tasting as you go to avoid over-salting before using all the seasoning.
10
Once evenly coated, plate and serve the crispy, juicy salt and pepper popcorn chicken.