Sweet and sour Chinese chicken balls

Name: Sweet and sour Chinese chicken balls
Prep time: 15 min
Cook time: 20 min
Total time: 35 min
Cuisine: Asian, Chinese
Ingredients: 120g self-raising flour; 1 tsp baking powder; Water; 2 chicken breasts (diced into small chunks); Vegetable oil; 1 red pepper, deseeded and diced; 1 x 432g can pineapple chunks, drained; 3 tbsp soft brown sugar; 4 tbsp cider vinegar; 4 tbsp tomato ketchup; 235ml water; 1 tbsp cornflour