750g chunk squash, peeled and chopped into 2cm pieces
1 tbsp sunflower oil
2 onions, chopped
thumb-size piece ginger, chopped
1 green chilli, halved
2 tsp black or brown mustard seeds
1 tsp ground coriander
2 tsp turmeric
2 tbsp cornflour
250g caster sugar
250ml cider vinegar
To make the pickle, cook the squash in boiling water for 6-10 mins until just tender but not falling apart. Drain gently.
Heat the oil in a pan and fry the onions, ginger and chilli for 10-12 mins until soft. Add the mustard seeds, ground coriander and turmeric for 1 min. Stir in the cornflour, then the sugar, then gradually stir in the vinegar. Simmer for 6-8 mins until thickened. Gently stir in the squash until just hot, then divide between 2 hot, sterilised jars and cover. Cool completely. The pickle can be eaten straight away or left in the fridge, unopened, for up to 1 month.
Put the lamb into a dish. Mix together the yogurt, ground coriander, turmeric, nearly all the chopped coriander, the lemon zest and juice and marinate for 1 hr or up to 1 day.
Griddle or pan-fry the lamb for 1-2 mins on each side until cooked to your liking, then scatter over the remaining coriander and eat with spoonfuls of pickle and naan.