To make the coconut chutney, mix all the ingredients in a bowl and leave to one side.
Bring a pan of water to the boil, then add the peas an bring back to the boil (cooking the peas according to pack cooking instructions). Remove from the heat, drain the peas and refresh under cold water.
Place approximately a third of the peas into a blender with 150 ml cold water and process to a smooth purée. Put the remaining peas and the pea purée to one side.
Finely chop the garlic, ginger, chillies and salt and mix.
Heat the vegetable oil in a pan until hot. Add the mustard seeds, cumin seeds, garam marsala and turmeric. Fry, stirring constantly, for 30 seconds before adding the onion.
Reduce the heat down and cook the onion with the spices for 4-5 minutes until they are soft and translucent, stirring frequently. Add the garlic, ginger and chilli paste. Cook for another 3 minutes, stirring frequently.
Add the coconut milk, the pea purée, and curry leaves (if using). Stir and reduce the heat to low. Bring to a simmer and cook for a further 10 minutes until the liquid has reduced, stirring occasionally.
Add the remaining cooked peas and bring to a simmer.
To temper the dal, add the oil to a frying pan on a low heat. Add the chillies, cumin and coriander until it crackles. Add curry leaves for ten seconds then remove and pour over the dal.
Remove the dal from the heat and serve with the chopped coriander, flatbreads or rice and the chutney.