Aubergine curry with lemongrass & coconut milk

INGREDIENTS

• 3 large red chillies , deseeded and stalks removed, chopped
• 6 garlic cloves , roughly chopped
• knob of fresh ginger , peeled and chopped
• 2 lemongrass stalks, trimmed and chopped
• 2 tbsp ground turmeric
• 1 tsp chilli powder
• 2-3 aubergines (about 600g/1lb 5oz), quartered lengthways, then halved
• 1 tbsp olive oil
• 1 tbsp sugar
• 6 shallots , finely chopped
• 1 tbsp Thai fish sauce (nam pla)
• 400ml can coconut milk
• 400ml vegetable stock or water
• small bunch coriander , roughly chopped, to serve