1. In a large bowl, combine 3 Tbs. olive oil, the garlic, fish sauce, sugar, pepper, and salt and stir until the sugar and salt are dissolved. Add the beef and toss o coat. Marinate for 20 min. Or refrigerate up to 3 hrs.
2. In a large, heavy skillet heat remaining 3 Tbs olive oil over high heat until smoking. Add the onions and stir-fry until slightly softened, about 4 min. Strain the bee, discarding the marinade. Add to the skillet and cook, tossing for 6-7 min. top with cilantro.
