In a bowl, add the beef stripes and mix in the Chinese 5 spice and set aside.
Prepare the sauce, in a small bowl add the soy sauce, rice vinegar, water, sugar, ginger and chilli powder and set aside.
Heat the oil in a pan, add the beef strips and fry for around 5mins until browned all over. Transfer to a plate and set aside.
Add the onions, peppers, chilli and garlic to the pan and fry until the vegetables begin to soften, but not too soft as you will want a bit of a crunch.
Return the beef to the pan, stir in the sauce and cook for a few mins.
Serve alongside some plain or egg fried rice, or even some noodles with some spring onions sprinkled on top and some shop bought prawn crackers on the side.