Preheat the oven to 180°C fan/350°F/Gas 4.

Heat the oil in a large saucepan set over a low heat and cook the onion and garlic with some salt for about 8 minutes, until softening. Stir in the spices and chillies, then add the sweet potato and cook for 2 minutes, stirring to cover it in the spiced oil.

Add the stock, bring to the boil and cover with a lid. Reduce the heat slightly and leave to simmer, for 15 minutes, or until the sweet potato is tender.

Meanwhile, put the tortilla quarters (see ingredients overleaf) on a large baking sheet.

Combine the oil and smoked paprika in a small bowl and brush this over the tortillas. Turn them and brush the other sides too, then sprinkle generously with sea salt flakes. Bake for 5–6 minutes, then turn them over and bake for a further 5–6 minutes, until turning crisp and golden.

Remove them from the oven and allow to cool (they will continue to crisp up as they cool).

Once the sweet potato is cooked, blend the soup with a stick blender or transfer to a liquidizer and blitz until smooth. Add the lime zest and juice, season to taste and blitz again to combine.

Ladle the soup into warmed bowls and top with the avocado. Snap the tortillas into shards and scatter a few over the top, serving any extra in a bowl. Finally, sprinkle with coriander and serve.