These give smokiness in the spiced beef, sharp heat from the pico de gallo, tangy creaminess in the refried beans, and butteriness in the guacamole – a flavour explosion in every bite. Make the tortillas ahead of time to allow for soaking.
Make the tortillas. Put the yellow field corn into a stainless steel or cast-iron pan, cover generously with water and stir in the calcium hydroxide until well mixed. Bring the mixture to the boil, then reduce the heat and simmer, stirring occasionally and adding more water as necessary to cover the corn, for 30 minutes, until the outer skin of the corn slips off easily, and the kernels are slightly cooked on the outside but remain dry and uncooked inside.
Remove the pan from the heat, cover with a lid and leave the corn to stand for at least 8 hours, or overnight. After soaking, drain the corn in a colander, then rinse it under cold running water, rubbing the kernels between your fingers to dislodge the skins, until the water runs clear. Leave to drain before use.
Tip the prepared corn into a food processor with the salt and 2 tablespoons of water and blitz for 3–5 minutes, scraping down the inside of the bowl from time to time, to a smooth, thick paste – it may still feel a little sandy, but not grainy.
Tip the corn paste onto the work surface and mix in the masa harina to form a dough that is neither sticky nor dry. Cover and leave to stand for 30 minutes. (If you’re using just masa harina flour – instead of a combination of yellow field corn, calcium hydroxide and masa – put 100g masa flour in a mixing bowl with 140ml of water and the salt and stir until combined. Leave to stand for 20 minutes.)
Prepare the beef. While the corn mixture is resting, mix the dried spices, oregano, salt and sugar in a bowl. Rub the spice mixture all over the steaks, then marinate it at room temperature for 1 hour.
Make the pico de gallo. While the steaks are marinating, place the tomato, onion and chilli in a bowl. Stir in the lime juice and salt and leave the mixture to stand for at least 1 hour. Stir in the coriander.
Make the refried beans. Heat the oil in a pan over a medium heat, add the onion and cook, stirring occasionally, for 5 minutes, until softened. Add the garlic, chilli powder, cumin and salt and cook, stirring continuously, for 1 minute, until the cumin releases its aroma. Add the black beans and 4 tablespoons of water and bring the mixture to the boil. Reduce the heat slightly and simmer for 5 minutes, until heated through. Using a potato masher, mash half of the beans, then stir everything together and stir in the lime juice. Cover and set aside until ready you’re to serve.
Make the guacamole. Place the tomato, onion, chilli, lime juice and coriander in a bowl and stir well to mix. Add the salt, then gently fold in the avocados. Taste and adjust the seasoning, if necessary.
Shape the tortillas. Divide the rested tortilla dough into 8 balls (about 30g each). Heat a dry, non-stick frying pan over a medium heat. On the work surface, place a ball of dough between two sheets of food-grade plastic or in a freezer bag large enough to accommodate the flattened tortilla. Using the flat lid of a casserole dish or tortilla press, press the dough flat into a thin 12cm disc.
Heat a dry frying pan over a medium heat. Peel off the plastic or take the tortilla out of the freezer bag and place it in the pan. Cook for 1–2 minutes, until the tortilla puffs up slightly. Flip the tortilla and cook the other side for another 2 minutes, until cooked through. Wrap the cooked tortilla in a clean tea towel to keep it warm while you press and cook the remainder to give 8 tortillas in total.
Cook the beef. Heat a large frying pan over a high heat and add the corn oil. Add the steaks and cook for 2–3 minutes on each side for medium rare. Remove the steaks from the pan and leave them to rest for 3 minutes, then thinly slice.
To serve, place the tortillas on a serving board and top each one with equal amounts of the refried beans and guacamole. Top with the sliced beef and pico de gallo, then crumble over the queso fresco or feta. Serve immediately.