Pineapple Chicken Soup recipe

1 med onion, thinly sliced
2 tbsp vegetable oil
1 med tomato, coarsely chopped
2 cup fresh pineapple, coarsely chopped
4 cup chicken stock
1 tsp lemongrass
1 pch hot chili peppers, crushed dried
1 tbsp fish sauce
1 cup chicken white meat, cooked and shredded
1/2 cup coriander leaves, chopped

In a medium saucepan saute the onion in the oil over moderate heat until it wilts.
Add the tomato, pineapple, stock and lemongrass, hot peppers, and fish suace. Simmer uncovered, over low heat for about 1/2 hr.
Stir in the chicken, then the coriander. Bring to a simmer. Serve hot.