Tamarind adds a sour note to this eggplant masala recipe. You can buy it (as well as chilli oil) easily at Asian markets. This is a lovely eggplant stew.
Sprinkle one tablespoon curry powder over the eggplant and leave to marinate 30 minutes.
Heat the chilli oil in a wok and fry the shallots, garlic, ginger and chilli for 30 seconds until softened, then add the other tablespoon curry powder.
Add the eggplant, tamarind, fish sauce and tomatoes and cook for 10 minutes until the eggplant is soft. Stir in the yoghurt and coriander and heat through. Serve immediately.