Cut the chicken into pieces; cut the pork into 2cm-thick slices.
Heat the oil to sauté the shallot and garlic paste until fragrant, stirring continuously. Add the bean paste and fry until the oil starts to separate.
Add the pork if using and fry for 5 minutes. Add the mushrooms and water, and bring to a boil. Lower heat and simmer for 20 minutes before adding chicken. Continue simmering until chicken and pork are tender, adding the potatoes and yambean half way through. Add more water if gravy becomes too thick. Season to taste with sugar and salt. Serve with sambal belacan.
Note: Pongteh tastes better the next day when the flavours are infused into the meat.