1 Purée the onion in the small bowl of a food processor or in a mini chopper; remove and set aside. Next puree the ginger and garlic with a splash of water; set aside.
2 Heat 2 tbsp coconut oil in a large frying pan and shallow fry the tilapia until golden, about 2 minutes each side (you may need to do this in batches). Remove from pan, drain on kitchen paper and set aside
3 Fry the aubergine for 4-5 minutes until golden on all sides (in batches if needed, adding more oil as you go). Drain on kitchen paper and set aside.
4 Add the onion purée to the pan (and a small amount of oil if the pan is dry) and cook for 2-3 minutes until it starts to dry out. Add the garlic/ginger paste, curry leaves, chilli and cook for 3-4 minutes until fragrant.
5 Add the dry spices and tomatoes and cook until it begins to dry. As soon as it starts to dry add the coconut milk a little at a time. Once all the coconut milk has been added, add the stock a little at a time. This process is essential as it allows the spices to become fragrant and cook through without burning. Once all the coconut milk and stock has been added, reduce heat and simmer gently for 5 minutes.
6 Return the fish and aubergine to the curry, take off the heat, allowing the residual heat of the pan to warm everything through. Garnish with the chopped coriander, a drizzle more coconut milk and extra chopped chilli (if you like it hot!).