Steps
1. In a bowl, mix the chicken pieces with beaten egg and cornstarch until well coated.
2. Heat vegetable oil in a pan over medium heat and fry the chicken until golden and cooked through. Remove and set aside.
3. In the same pan, sauté bell pepper and pineapple chunks for 2 minutes.
4. In a small bowl, combine ketchup, rice vinegar, soy sauce, brown sugar, and water.
5. Pour the sauce mixture into the pan and bring to a simmer.
6. Stir in the cornstarch slurry and cook until the sauce thickens.
7. Return the chicken to the pan and toss to coat evenly with the sauce.
8. Serve hot with steamed rice or noodles.