300g dried flat rice noodles - soak about 40min in water (according to the package instruction)
1. Combine ingredients A in a bowl and let the beef marinate for about 10min.
2. Heat 1 tablespoon of oil in a large skillet or a wok over medium-high heat until hot. Add beef and sear until browned. Transfer onto the plate and set aside.
3. In the same skillet (or wok) add another 1 tbsp oil and fry the garlic until fragrant. Add the onions. Stir-fry lightly and transfer onto the plate.
4. In the same skillet again, heat 1 tbsp vegetable oil and add the soaked noodles. Once remove from the heat, add the sauce ingredients (sesame oil, oyster sauce, dark soy sauce, soy sauce and brown sugar). Turn on the heat back.
5. Mix and stir-fry all together. Once the noodles are a little soft, add the bean sprouts, leek. Then stir-fry until the bean sprouts are just tender (about 30 seconds). Finally add the beef and onion. Stir-fry for a few minutes.