Slice beef fillet thinly, spread on the cutting board and season well with freshly ground black pepper.
Peel and mince garlic and ginger. Peel and finely dice Spanish onion. Chop spring onions finely. Top and tail beans and chop into bite-sized pieces. Cut broccoli or broccolini into florets, chop stems as well.
Heat 2 tablespoons oil in a wok or a fry pan until hot and fry beef slices in batches – only one layer should cover the pan at any time.
The meat will only take about 10-20 seconds to brown on each side. Flip using tongs and brown the other side. Place the meat in a bowl, set aside and repeat with the remaining slices.
Wipe down wok with some paper towel. Add 1 tablespoon oil and return to heat. Add garlic, ginger, onions, spring onions, beans and broccoli or broccolini. Stir fry until onion has separated and started to caramelise. Add mushrooms and stir fry for another couple of minutes.
Return beef to the wok and add sauce mixture. Stir fry for a minute for the sauce to thicken and coat the meat and vegetables.
Serve with steamed brown rice.