Cut the pumpkin and ashgourd into 2-inch pieces of half inch thickness and boil them together with salt and a bit of water. Both these vegetables have high water content. So no need to add a lot of water.
Once they are soft and boiled, add the boiled red cow pea (vanpayar) to the mixture and stir. Add the cut green chillies and let it simmer for 5-10 minutes.
Add the coconut milk to the mixture and stir. Once the coconut milk just comes to boil, turn off the flame and garnish with curry leaves. Add a tsp of coconut oil on the top and cover the dish. (Do not let the coconut oil boil for long as it tends to change the texture of the curry)