Combine all of the marinade ingredients in a bowl. Slice the steak into strips and add to the bowl ensuring that it is all coated. Cover and pop in the fridge while you prep the vegetables.
Cut all of the vegetables into even strips (julienne) ready for stir frying.
Heat a tablespoon of oil in the wok (or skillet) on the highest heat. Let the oil get super hot.
Add the onions to the wok for a minute or two to soften, keep moving them around in the wok as they cook. Add in the beef along with all of the marinade , and cook for a couple of minutes, again, keep stirring.
Once the beef has coloured, stir in the vegetables and cook for 3 minutes until they have softened, but still crunchy
Garnish with spring onions and some chilli slices. Serve immediately with rice or noodles
Notes
Place the steak in the freezer for 5 to 10 minutes before slicing it. This will make it easier to cut even strips.
Cut all of your veggies before you start cooking. Stir fries cook quickly, so have everything ready to use when you turn on the heat.
Your wok or skillet should be as hot as it can be.
Use a neutral high heat cooking oil like avocado, canola or vegetable. Olive oil should be avoided.