01 -
In a mixing bowl, combine granulated sugar, apple cider vinegar, ketchup, soy sauce, brown sugar, sesame oil, and minced garlic. In another small bowl, blend cornstarch with a splash of water to make a smooth slurry. Set both aside.
02 -
Pour canola oil into a large skillet or wok to a depth of 1 inch and heat over medium-high until temperature reaches 375°F.
03 -
Season chicken pieces with salt. Dredge each piece in cornstarch, dip into beaten egg, and then coat thoroughly with flour.
04 -
Fry chicken in batches, ensuring pieces are not overcrowded, turning as needed until golden and crisp on all sides, about 4–5 minutes per batch. Transfer to a wire rack to drain excess oil.
05 -
Carefully remove most of the frying oil from the pan, leaving about 1 tablespoon. Increase to high heat, add chopped onion, red bell pepper, green bell pepper, and optional pineapple. Cook, stirring occasionally, until just charred, about 3 minutes.
06 -
Whisk the prepared sauce to recombine, pour it into the hot pan with the vegetables, and mix well. Stir in the cornstarch slurry. Bring to a simmer and cook, stirring, until sauce thickens and becomes glossy, about 3 minutes.
07 -
Return fried chicken pieces to the wok, tossing thoroughly to coat with sauce and vegetables. Serve immediately while hot.