Heat the oil in a large wok or frying pan. Add the onion and green curry past and cook, tirring, over medium heat for 3 minutes. Add the eggplant and cook for a furth 4-5 minutes or until softened.
Pour in the coconut milk and vegetable stock, bring to a boil, then reduce the heat and simmer for 5 minutes. Add the makrut leaves and sweet potatoes and cook for the 10 minutes, or until eggpplant and sweet potatoes are very tender.
Mix in the sugar, lime juice and zest until well combined with the vegetables. Season to taste with salt and serve over jasmine rice.