To marinate the chicken wings, poke the chicken wing flats all over with bamboo skewers or a fork to help the marinade absorb more quickly. In a bowl, add the wings, soy sauce, oyster sauce, rice wine, white pepper, and grated garlic. Mix well and let marinate for at least 5 minutes, or longer for deeper flavor.
To coat the wings, crack the egg directly into the bowl with the marinated wings. Add the rice flour and mix until each wing is evenly coated.
To fry the wings the first time, in a pot over high heat, add the cooking oil and heat to 325°F (163°C). Carefully add the wings one at a time and fry for about 5 minutes until fully cooked. Remove and let drain briefly.
To fry the wings the second time, increase the oil temperature to 350°F (177°C). Return the wings to the oil and fry for another 2 minutes until deeply golden and extra crispy. The internal temperature should reach at least 165°F (74°C). Remove and drain well before serving.