How to Make It
Preheat the oven to 425°. In a medium bowl, whisk the egg. In another medium bowl, whisk together the cornstarch and 1/4 teaspoon each of sea salt and freshly ground pepper.
Dip all of the chicken into the egg, stir to coat. One piece at a time, remove the chicken from the egg and turn in the seasoned cornstarch, making sure each piece is well coated.
In a medium ovenproof nonstick frying pan, heat the oil. When the pan is hot add the chicken, giving the pan a little shake after each addition to prevent it from sticking. Cook for about 1 minute per side, until brown and crispy. Remove the pan from the heat.
Whisk together the brown sugar, ketchup, apple cider vinegar, soy sauce, garlic and 1/8 teaspoon of sea salt. Pour the sauce over the chicken.
Place the chicken in the oven and bake for 10 to 15 minutes, or until the thickest part of the chicken pieces registers 165° on an instant-read meat thermometer.
Remove the chicken from the oven and carefully pour the sauce into a small saucepan. Boil over high heat for 3 to 5 minutes, until it is thick enough to coat the chicken well. Add the chicken to the saucepan and toss to coat.