Heat the oil in a frying pan and cook the onion for 5 minutes, then the garlic for a minute.
Add the mince and brown well, 8 minutes. Add the cumin, paprika, oregano and cayenne and **fry for a full minute** before any liquid goes in.
Stir in the tomato paste, tinned tomatoes and beans. Simmer for 10 minutes until **thick enough to hold a spoon shape** — not saucy. Season well.
Heat the oven to 200°C (180°C fan).
In a wide shallow baking dish, spread **half** the corn chips. Scatter over a third of the cheese, then half the mince, then another third of the cheese.
Add the remaining chips, the rest of the mince, and the last of the cheese.
Bake for 10–12 minutes, until the cheese is melted and bubbling and just starting to colour at the edges.
Take it out and **now** add the sour cream, avocado, tomato, spring onion, coriander and jalapeños.