Rub salt and pepper all over the chicken. Let it stay for 15 minutes.
Heat the oil in a cooking pot.
Combine flour,cornstarch, garlic powder, salt, and ground black pepper. Mix well using a fork or a wire whisk. Set aside.
Dredge the chicken in breading until completely covered. Fry in medium heat for 7 minutes per side.
Melt butter in a large pot over lowest heat. Whisk in flour, and let it cook, whisking constantly for about 1 minute.
Pour and whisk in chicken broth and remaining ingredients.
Let it simmer over low heat, whisking constantly, 2 minutes or until mixture thickens.
Sprinkle little sugar and season with salt to taste. Keep whisking to smoothen sauce and dissolve the lumps. Turn off heat once gravy is smooth and thick.