- Fill the inner pot with 1.5L water and bring to a boil.
- Add in Chinese mustard, mushrooms, whole garlic, dried chilies and asam keping, cover the pot and boil it with medium-low heat for 20 minutes.
- Add in roasted duck and roasted chicken boil it with medium-low heat for 10 minutes.
- Add in salt, tomato sauce, oyster sauce, boil it with medium-low heat for another 10 minutes.
- Turn off heat and transfer the inner pot into the vacuum outer pot and heat insulating cooking for 1 hour before serving.
