Heat the oven to 200C fan, gas 7. Put the aubergines in a large roasting tin, drizzle with 2tbsp of the olive oil and season to taste. Roast for 15-20 minutes or until the flesh is soft.
Heat the remaining oil in a large pan. Add the red onions and fry gently for 5 minutes. Add the sugar and curry paste, and cook for a further 2 minutes or until caramelised and bubbling. Stir through the ground almonds, coconut milk and yogurt, and bring to the boil. Simmer and cook, covered, for 20 minutes or until reduced and thickening. Season to taste. Add the aubergines to the pan along with the mustard seeds and cook for a final 10 minutes. Stir in the coriander, and serve with naan breads or rice.
