Slice your steak into very thin strips, approx 1/2cm in diameter, length doesn't matter
In a separate bowl, mix your cornflour, salt, pepper and 5 spice in a bowl
Pop the steak into the cornflour mix and coat the strips
Heat 100ml oil in a frying pan until hot, drop the beef in a fry until golden (looks a bit weird) this will take about 5 minutes or so
Cook your noodles or rice at this stage
Once the beef is golden - lift out and place on kitchen roll and pop on one side
Then tip oil out of frying pan and add 1 tsp oil backing the pan. Add the chopped garlic, ginger, chilli and fry for 2 mins, then add spring onions, peppers and mushrooms, fry for approx 2 mins until soft
Mix rice wine vinegar in bowl with soy sauce, sweet chilli sauce, ketchup and approx. 1 tbsp water, stir
Tip this mix into frying pan and heat for 2 minutes, it should be bubbling.
Throw in the beef and heat for 1 minute
Finally Serve - put noodles or rice on plate and beef mix on top, finish with chopped spring onion
Notes
*** All nutritional information is approximate and intended as a guide