1. Peel and finely chop the red onion. Put a medium pan on a medium heat and add ½ tbsp olive oil to the pan. Add a pinch of salt and cook, stirring every so often, for 5 mins till the onion starts to soften and caramelise.
2. While the onion fries, peel and dice the sweet potatoes. Stir the sweet potatoes into the onion and fry for a further 8 mins, stirring often, till veg have softened a little.
3. While the veg fry, peel and finely chop or grate the garlic cloves. Halve the chilli and scoop out the seeds and white pith (or leave them in for a hotter flavour). Finely chop the chilli. Finely chop the coriander stalks. Drain the kidney beans and rinse them under cold water.
4. Stir the kidney beans into the pan and add the garlic, chilli, coriander stalks and 2 tsp Cajun seasoning. Cook, stirring, for 2 mins.
5. Pour in the passata. Stir to mix, pop a lid on the pan and simmer for 10 mins. Meanwhile, preheat your oven to 200°C/Fan 180°C/Gas 6.
6. After 10 mins, check the chilli. The sweet potatoes should be tender. Take the pan off the heat, taste and add a pinch more salt if you think it needs it. Lay 1 tortilla on your work surface and spoon 2 tbsp of the kidney bean and sweet potato chilli onto one half of the tortilla. Roll it up and lay the tortilla in a small ovenproof dish. Repeat with the remaining 3 tortillas. Spoon the rest of the sweet potato sauce over the tortillas. Slide the dish into the oven and bake for 15 mins.
7. While the enchiladas bake, halve the avocado and scoop out the stone. Scoop the flesh out of the skin and slice the avocado halves.
8. When the enchiladas are bubbling and a little golden, take them out of the oven. Divide the enchiladas and their sauce between 2 warm plates and serve with avocado slices on the side, garnished with the coriander leaves.