Heat pan on medium. Add chopped onion and stir occasionally until soft.
Roughly chol garlic and grate ginger and add to pot.
Slice potato into medium peices and add to pot with salt
Add all spices into heated mixture and stir for around 5 min
Pour coconut milk into pan, stir and cook for 2min
Dissolve vegetable stock in water
Add stock water, soy sauce and lentils
Bring pot to boil, then allow to simmer for 40min.
When finished, add butter and extra water if needed