Prepare microwave grains according to packet instructions. Set aside.
Meanwhile, place beef in a large bowl or snap-lock bag, add half the oil and toss to coat. Heat a large wok or non-stick frying pan over high heat. Stir-fry beef, in batches, for 1-2 minutes or until browned. Set aside on a plate.
Add remaining oil to wok or pan over medium-high heat. Add garlic and onions and stir-fry for 1 minute. Add broccolini and brussels sprouts and stir-fry for 2-3 minutes. Add mushrooms and stir-fry for 1 minute. Stir in sauces and 2 tablespoons water and cook for 1 minute. Return beef to wok, add ancient grains and toss to heat through. Season.
Serve stir-fry topped with extra green onions and coriander sprigs.
Beef mince would be a delicious substitute for rump in this recipe.
When stir-frying the meat wait at least 30 seconds before tossing or stir-frying. This gives the meat a chance to brown, giving it good colour and flavour.
The second side will take a little less time to cook.
Once you return the meat to the wok, take care that it does not boil in the liquid or it will toughen. Stir-fry only to combine and warm through.