Slice sirloin 1/8 inch thick.
In a saucepan put in the meat, vinegar, soy sauce, garlic,laurel leaf and peppercorns. Boil the meat over low heat. Leave uncovered until the smell of vinegar dissipates, DO NOT STIR.
Add water when needed.
Cover and let simmer until meat is very tender.
Season with salt.
Slice the white onions into rings.
In a frying pan, saute the onions till wilted. Remove from pan.
Put in the meat, reserve the liquid it was boiled inches
Brown the meat. Add the reserved liquid. Let it simmer till liquid has been reduced.
Transfer meat to a platter, pour sauce over. Top with sauteed onions. Serve hot with Jasmine rice.