Fry off ginger, garlic, onion, lemon grass in oil until onion is translucent. Add to large cooking pot or pressure/slow cooker.
Add all other ingredients to pot and add enough water to only just cover veg.
Pressure cook for 35mins or Simmer on stove top for a few hours or slow cook for 8hrs.
Pour in to blender blitz until smooth. Serve and garnish with coriander.