Start by prepping the ingredients. Cut the chicken into bite size pieces. Roughly chop the oyster mushrooms. Clean and slice the galangal into rounds. Cut the ends of the lemongrass, bruise it with a rolling pin or the back of your knife and cut into pieces. Slice the chillies for more heat or leave them whole if you like them less spicy.
Get a wok or a saucepan on the stove on a medium high heat and add the water. Season it with the salt and add in the lemongrass, galangal and the shallots.
Once the water comes to a boil add the chicken pieces in and simmer for 10 minutes.
Then add in the coconut cream, red chillies, fish sauce, kaffir lime leaves (make sure to tear them), white pepper and mushrooms.
Simmer on a gentle heat for about 10 minutes till the mushrooms and chicken is fully cooked.
Turn off the heat and add in the lime juice and coriander. Taste for seasoning and adjust to taste. More lime juice if you like it sour.