Rinse the chicken breasts in water and pat dry. Cut into bite-sized pieces like you would get when you order at a Chinese restaurant. Season with salt and pepper.
Dip the chicken pieces into the cornstarch to coat, then dip them in the egg.
Heat the 1/2 c. of oil in a large skillet and brown the chicken on both sides-just enough to brown but not cook them all the way through. Place on a plate covered with paper towel to remove excess oil.
Place the chicken in a greased 9×13 baking dish. Mix all of the sweet and sour sauce ingredients together in a bowl with a whisk then pour evenly over the chicken.
Bake for 45 minutes at 350°, turning the chicken halfway through baking. Serve over rice.