Add the potatoes to a large pot of salted water. Bring to a boil and cook 15–18 minutes, until just fork-tender. Drain well and allow them to steam dry for 2–3 minutes.
Smash
Preheat oven to 220°C (425°F). Line a large baking tray with parchment. Place potatoes on the tray and, using the base of a glass or jar, press each to about 1 cm (½ inch) thick.
Season & Roast
In a small bowl, combine smoked paprika, garlic powder, salt, and pepper. Drizzle potatoes evenly with olive oil, then sprinkle the mixed seasoning across the tray. Toss gently to coat. Roast for 25–30 minutes, flipping halfway, until crisp and golden on both sides.
Add Cheese
Remove the tray and scatter the mozzarella and cheddar evenly. Return to the oven for 5–7 minutes, until cheese is melted and bubbling.
Top & Finish
Spoon over salsa and smashed avocado. Drizzle with sour cream, scatter pickled jalapeños and spring onions. Optional: coriander, pickled onions, or hot sauce.
Serving & Removing From Tray
Use a thin metal spatula or fish slice to lift portions without breaking them. Serve directly on the tray for casual sharing, or transfer carefully to a platter. Best eaten straight away while hot and crisp.
Chef's Tips
Let the potatoes steam dry for the full 2–3 minutes after draining, before smashing — any leftover surface moisture will steam instead of crisp once they hit the hot oven.Smash firmly enough to create rough, jagged edges rather than just flattening them into neat rounds — those uneven bits are what catch and crisp first, giving you the crunch this dish is built on.Give the potatoes space on the tray rather than crowding them — packed too close, they trap steam between each other and stop the high heat from crisping the edges properly.
Storage & Reheating
This one's best eaten straight away, as written — the avocado, sour cream and salsa won't hold up sitting on a crisp base for long, and the potatoes will lose their crunch fast once topped.If you do want to prep ahead, roast and cheese the potato base only, then store it plain in the fridge for up to 2 days. Reheat in a hot oven or air fryer for 6–8 minutes to re-crisp, then add the avocado, salsa, sour cream and remaining fresh toppings just before serving.