Detach the bok choy stems from the leaves. Cut the stems into small pieces and leave the whole leaves intact.
Remove the foam that sits above the broth and add ¾ cup (200 ml) of boiling water.
Add the bok choy stems and cook for 5 minutes.
Add the bok choy leaves and cook for 1 minute.
Remove from heat and serve hot with a mixture of soy sauce and lime or calamansi juice.