01 - 
                Cut chicken into bite-sized pieces.
              
              
              
                02 - 
                In a bowl, mix oyster sauce, soy sauce, black pepper, cornstarch, salt, and water until well combined.
              
              
              
                03 - 
                Heat vegetable oil in a pan over medium heat. Add the chicken and cook until golden brown, about 5-7 minutes.
              
              
              
                04 - 
                Stir in onions, garlic, mushrooms, and green bell pepper. Cook for another 3-4 minutes until softened.
              
              
              
                05 - 
                Pour the sauce over the chicken and vegetables. Stir well and cook until the sauce thickens, about 2-3 minutes.
              
              
              
                06 - 
                Drizzle with sesame oil, give it a final stir, and serve hot with rice.