Tom yum goong (coconut milk fish tom yum soup)

Ingredients

• 1 inch galangal/lengkuas
• 1 lemongrass
• 4 shallots
• 1/2 inch ginger
• Red or birds eye chilies (as needed)
• ** Pound/process into a rough paste
• Other ingredients
• 1 large piece (about 400g) mackerel - cut into bite sizes
• 5-6 kaffir lime/limau purut leaves - tear into pieces
• 1 cup thick coconut milk
• 1 packet oyster mushrooms
• 1 tbsp fish sauce
• 1 tbsp lime juice
• 1/2 tbsp sugar
• 3 tbsp oil
• Salt for taste