1.Heat oil in a deep frying pan on medium. Cook paste with onion, lemongrass, cardamom and mustard seeds for 2-3 minutes, until fragrant.
2.Add eggplant and pumpkin and stir to coat with paste. Pour in coconut milk and 1 cup water. Bring to a simmer and cook for 15 minutes or until pumpkin is tender. Add chickpeas and cook for 5 minutes, until warm. Remove lemongrass.
3.Squeeze juice of 1 lime into curry, then cut cheeks from remaining lime. Scatter cashews over curry and serve with mint, lime and naan bread.