Marinate beef dices in Lee Kum Kee Panda Brand Oyster Sauce for 10 minutes. Slice and discard top off each bell pepper, remove seeds from inside, rinse well to clear and pat dry with cloth.
Sauté beef with olive until golden, drain and set aside. Toss capsicum and pineapple dices in to stir-fry. Put cooked beef back into frying pan, and add sauce ingredients in to heat until it thickens. Arrange beef and pineapple with sauce on bell peppers to serve.