1) Cut the sirloin into 2 mm thick slices, put them into a bowl, transfer in 1 teaspoon (5ml) of raw soy sauce and water starch, and marinate for 10 minutes.
2) Soak the dried rice noodles in warm water of about 50 ℃ for 5 minutes. When the rice noodles become soft, remove and drain the water for standby.
3) Cut the onion into thin shreds. Wash the leek and cut into 5cm long sections. Peel the ginger and cut it into shreds.
4) Put the oil in the pot and heat it in high heat. When the oil is 70% hot, put in the fillet of beef. Stir fry for half a minute. Remove the discolored meat.
5) Wash the pot, dry the water, heat it and pour in the cool oil. Immediately put the rice noodles, onion, ginger and mung bean sprouts,
6) Stir gently with chopsticks and stir for 3 minutes (it is best to stir the pan, so as not to stir the rice noodles), stir until the rice noodles are 9 mature.
7) Put in the sirloin slices, mix in the remaining soy sauce, soy sauce, sugar and salt, continue to stir gently with chopsticks.
8) Before leaving the pot, put in leek and fry for 10 seconds.