Sauté the aromatics: Heat the olive oil in a large, ovenproof skillet over a medium-high flame. Add the diced onion and cook for 4–5 minutes until it turns translucent and softens — you’ll smell a sweet, savoury aroma rising from the pan. Stir occasionally so it doesn’t catch.

Brown the beef: Tip the minced beef into the skillet. Break it apart with a wooden spoon and let it brown undisturbed for 2 minutes, then stir. Continue cooking until all the pink has vanished and the meat is a rich, deep brown colour. The sizzling sound will quieten once the moisture has evaporated — that’s your cue that it’s ready.

Bloom the spices: Sprinkle the cumin, smoked paprika, and oregano over the beef. Stir for 30 seconds until the spices become fragrant and coat every piece of meat. This step unlocks their oils, giving the casserole a deeper flavour.

Build the sauce: Add the garlic, tomato purée, and tinned tomatoes. Stir well, scraping up any browned bits from the bottom of the pan. Pour in the beef stock and bring the mixture to a gentle simmer. Let it bubble for 5 minutes — the sauce will thicken slightly and turn a vibrant, rusty red. Taste and season with salt and pepper.

Layer the casserole: Preheat your oven to 190°C (fan-assisted) or 200°C (conventional). Tear the tortillas into rough 5 cm pieces. Spread a thin layer of the beef sauce across the bottom of the skillet, then arrange a third of the tortilla pieces on top. Spoon another third of the sauce over the tortillas, scatter over half the black beans, and sprinkle with a handful of cheese. Repeat the layers — tortillas, sauce, beans, cheese — finishing with a final layer of tortillas, the remaining sauce, and a generous blanket of cheese on top.

Bake until bubbly: Place the skillet in the oven and bake for 20–25 minutes. When it’s done, the cheese will be melted and golden in patches, and the sauce will be bubbling up around the edges. You’ll hear a gentle pop and sizzle as it comes out of the oven. Let it rest on the counter for 5–7 minutes before serving — this allows the layers to set so you get clean, neat portions.