In a mortar and pestle, pound garlic and chilies into a paste.
Add the palm sugar and pound until dissolved.
Add cilantro stems and pound into a paste.
Add fish sauce and lime juice; swirl the pestle to mix. Store in the fridge in a tightly sealed container.
Combine all ingredients in the blender and blend on medium speed just until there are no more big chunks. You do not want to completely liquefy it; you want to see some visible chili seeds and little bits.
