Beef Stroganoff

Ingredients:

60ml cooking oil
1kg pounds beef sirloin steak, sliced across grain 1/2 inch thick
200g button mushrooms, sliced
2 medium onions, thinly wedged
2 cloves garlic, finely chopped
½ teaspoon salt
½ teaspoon pepper
100ml Lee Shun Hing Premium oyster sauce
15ml Worcestershire sauce
5 teaspoon corn flour
15ml LSH Sesame oil
50g butter
200g sour cream
1 tsp oregano
2 pcs bay leaves