Mix the red onion with half the lime juice and a pinch of salt in a small bowl, then set aside.

Heat the oil in a frying pan over a medium-low heat, and crumble in the mince. Cook for 15-20 mins – the mince will release some liquid, but once this has bubbled away, it will sizzle in its own fat. At this point, stir or toss with a wooden spoon so the mince browns and caramelises all over. If the pan becomes too dry, add a drizzle more oil. When the mince is well toasted, sprinkle over the taco seasoning and cook for 2 mins, then stir through the tomato purée and pour over the rest of the lime juice and let it sizzle for another minute. Stir through the black beans and turn up the heat to medium, continuing to cook until everything is hot. Taste for seasoning, then set aside.

To make the dressing, mix the lime juice with the soured cream and chilli sauce, if using, season, then set aside.

Scatter a handful of tortilla chips into a bowl, then add a layer of lettuce, then the mince and black beans. Top with the avocado slices, chopped tomato, pickled red onions, along with any juices, and the feta. Drizzle with the dressing, then finally scatter over the coriander. Tuck more tortilla chips around the sides of the bowl, then serve.