To begin, add the steaks to a large plate or mixing bowl and add the smoked paprika, ground cumin, chilli, dried oregano, and a generous pinch of salt. Rub all over the steaks, then add a healthy splash of cooking oil and the lime juice. Rub again and leave to marinate for 20-30 minutes.
While the steak is marinating, roughly slice the onions and de-seed the peppers and cut into strips.
Heat a cast-iron skillet or large frying pan until screaming hot and add the onions. Cook for 2-3 minutes, turning often, until lightly coloured, then transfer to a large saucepan and continue to cook over low heat, stirring often.
Add the peppers, skin-side down, to the hot skillet and cook over high heat until the skin blisters. This should take 2-3 minutes. Turn the peppers over and continue to cook for a minute or two.
Add the peppers to the saucepan with the onions and add 2 teaspoons of sugar. Increase the heat and stir often for a minute until the sugar dissolves and the onions and peppers begin to caramelise. Add a splash of water to deglaze the pan and continue to cook on high heat until the water dissolves. Once dissolved, reduce the heat to its lowest setting.
While the water is dissolving, add the steak to the hot skillet and cook over high heat for around 2-3 minutes on each side, or to your liking. Remove from the pan and rest for 5-10 minutes before slicing into approx. 8-10mm strips.
While the steak rests, return the peppers and onions to the skillet. Decrease the heat to the lowest possible and continue to cook while you warm the tortillas.
In a separate pan, warm the tortillas for 15-20 seconds on each side then eat as quickly as possible, filling the tortillas with the steak slices, onion-peppers mixture and optional toppings such as sliced avocado, guacamole, sour cream, salsa, cheese, refried beans, and a good pinch of fresh coriander.
