30 g (1 1/4 oz) Mexican spice mix (such as fajita seasoning)
4 large or 8 small soft flour tortillas
grated Cheddar cheese or Emmental
shredded Iceberg lettuce
Heat the oil in a large frying pan and cook the beef over a high heat for 2–3 minutes until browned. Add the onion and peppers and stir-fry for 2–3 minutes until the vegetables begin to soften and the beef is just cooked but still slightly pink. Sprinkle over the Mexican spice mix and stir-fry for a minute to cook the spices.
Divide the beef between the tortillas and top with your chosen fillings, then roll each tortilla tightly and cut it in half diagonally to serve.