Start by preheating your oven to 325 degrees. Rinse your chicken breasts in water and then cut into cubes. Season with salt and pepper to taste. Dip chicken into the cornstarch to coat then dip into the eggs. Heat your 1/4 cup oil in a large skillet and cook your chicken until browned but not cooked through. Place the chicken in a 9×13 greased baking dish. Mix all of your sweet and sour sauce ingredients in a bowl with a whisk and then pour evenly over the chicken. Bake for one hour and during the baking process you will need to turn the chicken every 15 minutes.