1，cut beef (200g) into slices. marinate with 1/4 tsp baking soda, 1 tsp oil, 1 tsp light soy sauce, 1 tbsp oyster sauce, 1/2 tsp black pepper powder, 1 tbsp corn flour and 3 tbsp water.
2, prepare vegetables: 2 stalk spring onion into about 5 cm piece, Cai Sim 100g (separate the leaf and stem), a small onion into slices, wash bean sprout about 150g and drain.
3, heat a pan, add in 2 tbsp oil. Add in beef. Stir fry with medium high heat and stir fry till no pinkish. Set aside for later use.
4, use the same pan to stir fry hor fun. Add in 2 tbsp light soy sauce, 1 tbsp vinegar, and 2 tsp dark soy sauce. Stir fry evenly and hor fun will become dark in color.
5, heat the pan again, add in a little bit more oil. Stir fry ginger slices and 3 chopped garlic till aromatic.
6, add in onion, and cai sim stems. Stir fry for 1 min.
7, Sprinkle 1/2 tsp salt. Add in cai sim leaves. Stir fry evenly for another minute.
8, add in beef. stir fry evenly.
9, Add in 1 tsp dark soy sauce, and bean sprouts. Stir fry for 2 mins.
10, add in hor fun. Stir fry evenly for 2-3 mins. Sprinkle spring onion and stir fry a bit.