Put the coconut milk and curry paste in a saucepan over a medium heat and stir well. Pour in the stock, then add the aubergines, sugar, soy sauce, ginger, and salt to taste.
Bring to the boil and cook, stirring, for 5 minutes. Add the mushrooms and green pepper, reduce the heat and cook for 2 minutes until piping hot.
Serve in bowls, drizzled with a little extra coconut milk.