Put the steak in a bowl with the spices
and garlic, and stir well. If you have time,
leave to marinate for a couple of hrs.
Heat the oil in a wok, then tip in the
beef and fry for just 1-2 mins, until it
changes colour but is still on the rare
side. Remove the beef to a plate.
Add the pepper and half the onion, and
stir-fry in the juices – add a splash of water
to get things going and stop it burning.
Stir in the tomatoes and beans, and heat
through with plenty of seasoning, then
stir in most of the coriander.
Meanwhile, heat the tortillas. The best way is directly on the gas flame, as it gives them a lovely charred flavour. Stir the beef into the beans and heat briefly. Serve with the tortillas and the reserved onion and coriander.