Beef stir-fry strips are convenient, but for the best flavour, slice your own steaks instead. Put them in the freezer for 10 mins then cut into thin slices with a sharp knife.
Heat a wok until smoking, pour in the oil then add beef. Stir-fry for 2 mins, then tip onto a plate. Add broccoli with a splash of water then cook until broccoli turns bright green.
Add the onion and stir-fry for 1 min, then
add the garlic and cook for 1 min more. Pour
in the oyster sauce and 125ml water. Bring
to the boil and cook until reduced to a sticky
sauce. Stir in the beef, along with any juices
from the plate, then serve straight away.