Once all the chicken is fried, heat a pan and add a tablespoon of oil. When the oil turns hot, add the chopped onion and garlic and fry until the onion turns translucent. Add tomato sauce, soy sauce and water and mix well. Add white pepper powder, salt and sugar and mix well. When the sauce thickens and starts bubbling, add the fried chicken pieces to the pan and toss to coat well. Once all the chicken pieces are nicely coated in the sauce, switch off. Serve hot. Enjoy!