Slice onion and celery. Cook in butter in a large covered frying pan for 2-3 minutes.
Coarsely chop capsicum and add to the pan. Cut pineapple pieces into smaller chunks, and brown them lightly with the vegetables.
Remove vegetables and pineapple from the pan.
Cut the chicken livers in halves, removing any membrane. Add a little more butter to the pan and raise the heat.
Add garlic and livers and cook until evenly browned for about 5 minutes.
Remove from the pan and reduce the heat.
Mix cornflour, tomato sauce, wine vinegar, instant chicken stock, soy sauce and pineapple juice and add to the drippings in the pan. Bring to the boil, and add the livers and vegetables, stirring to coat with sauce.
Taste and add a little sugar if desired.
Garnish with a sprinkle of spring onions and serve immediately on rice.