Squash and tomato curry with lime and coconut

Method

1. Using a large, very sharp knife, slice through the middle of the onion squash. Scoop out the seeds using a spoon, then slice into 5cm wedges and set aside.
2. Place a heavy-based pan over a medium heat. Add the oil and when it is warm, add the onion. Lower the heat and cook for 10 minutes until soft and translucent. Add the garlic, chilli, curry leaves and the coriander roots and stalks, and continue to cook gently.
3. Meanwhile, warm a small, non-stick frying pan over a medium heat, add the mustard and fennel seeds and cook until they just begin to pop – the heat will tickle out their. Remove from the heat and pound to a powder, using a pestle and mortar. Add to the onion curry base, stir to combine and cook gently for a further 5 minutes.
4. Add the onion squash, stir again and cook for 10 minutes, then add the sugar, fish sauce and lime juice. It is really important to get the balance of flavours right at this stage, so now is the time to taste and assess. The curry should be pleasantly (not aggressively) hot; sweet (but not sickly); sour (but not so much that it makes you squint); and salty enough to underpin and ground the dish.
5. Once you feel the flavours are just right, add the little ripe tomatoes – squishing them slightly between your fingers as you do so, to help them release their lovely flavour. Add the jar of plum tomatoes, too. Cook for a further 20–25 minutes until the squash is tender when pierced with a fork. Pour in the coconut milk and cook for a final 5 minutes or so.
6. The tomato and coconut milk enrich the curry, giving it a depth and smoothness that complete the dish. Turn off the heat and allow to cool. Reheat the curry gently and thoroughly when you are ready to serve. Like many wet dishes, this one improves in flavour if allowed to cool and sit before reheating.