Mix the flour, cornstarch, salt, pepper, vegetable oil, egg, and water together with a whisk.
Mix the cubed chicken into the batter so that all pieces are evenly coated.
Heat a pot of peanut oil or the oil of your choice. Once the oil is hot enough, carefully drop battered pieces of chicken into the pot with a pair of tongs. Depending on how crispy you like your chicken, the pieces should cook in the hot oil for 3-6 minutes.
Once the batter is crispy enough, collect the chicken pieces with a skimmer and let them drain on a paper towel-lined plate. Remove the pot from the stove and let the oil cool.
In a heated pan, roast the chili flakes, garlic, and ginger in the vegetable oil. Add the brown sugar and let the mixture caramelize while constantly stirring until golden brown. Then add the orange juice and white vinegar.
Mix 2 tablespoons of cornstarch and 2 tablespoons of water together in a bowl. Add the resulting milky liquid in spoonfuls to the other ingredients in the pan. Stir everything together.
Finally, add the battered chicken pieces, together with a teaspoon of sesame oil, and briefly fry them in the orange sauce until golden brown.
This Chinese dish is best served with a helping of Jasmine rice. Sprinkle some sesame seeds on top for a nice finish.
