If using fresh peas, remove the peas from their pods and set aside. Drain the soaked green gram, then rinse and drain again. Put the green gram in a saucepan with 1.5 litres (52 fl oz/6 cups) water and boil for 10 minutes, or until tender. Strain and put aside.
Using a mortar and pestle, pound the garlic, ginger and lemongrass into a paste, adding a little water. Pour 80 ml (2½ fl oz/⅓ cup) coconut milk into a clay pot or heavy-based saucepan and place over medium heat, then add the onion, rampe, curry leaves, chilli, pepper and the garlic, ginger and lemongrass paste. Fry for 3-5 minutes, stirring regularly. If the spices start to stick to the bottom of the pot, add a little water.
Stir in 60 ml (2 fl oz/¼ cup) water and deglaze the pot using a wooden spoon to scrape off any browned bits stuck to the pot. Add the korma spice mix, turmeric, cumin, salt, carrots, peas, cashews, coconut cream and the extra coconut milk. Use a flat spoon to flatten and pack down the curry. Bring almost to the boil and then stir through the green gram. Reduce the heat to low, cover and cook for a further 10-15 minutes, stirring occasionally, until the green gram and carrots are cooked and the liquid has almost evaporated. Serve as a side curry with chicken biryani or with rice.