Season the beef with pepper. Heat half a tablespoon of the oil in large, non-stick frying pan and stir-fry the beef (such as sirloin or rump, visible fat trimmed and cut into thin strips) for 1&1/2 minutes, or until lightly browned but not quite cooked through. Tip onto a plate, set aside and return the pan to the heat.

Add the remaining oil, peppers and onions to the pan and stir-fry for 5–6 minutes, or until only just softened. Add the cumin and paprika. Season with salt and black pepper and cook for 30 seconds, then stir in the cooked beef. Cook for 2–3 minutes, or until the beef are hot.

Stir in the chilli and season with salt and black pepper. Cook for a few seconds more. Remove from the heat, over a squeeze of lime. Toss lightly.

Divide the tortillas between four warmed plates. Top with shredded lettuce then pile the beef mixture on top. Spoon the yoghurt over each tortilla and Serve immediately, with extra lime wedges for squeezing.