Preheat the oven to 325 degrees F.
Cut the chicken breasts into 1-inch pieces. Season lightly with salt and pepper. Place the cornstarch in a gallon-sized ziploc bag. Put the chicken into the bag with the cornstarch and seal, tossing to coat the chicken.
Whisk the eggs together in a shallow pie plate.
Heat the oil in a large skillet over medium heat until very hot and rippling. Dip the cornstarch-coated chicken pieces in the egg and place them carefully in a single layer in the hot skillet.
Cook for 20-30seconds on each side until the crust is golden but the chicken is not all the way cooked through. Place the chicken pieces in a single layer in a 9X13-inchbaking dish and repeat with the remaining chicken pieces.
Mix the sauce ingredients (sugar, ketchup, apple cider vinegar, soy sauce, and garlic salt) together in a medium bowl and pour over the chicken.
Bake for 45 minutes to one hour, turning the chicken once or twice while cooking to coat evenly with sauce.
Serve over hot,steamed rice and add a green vegetable as a side dish.