Young ash gourd, covered in a fuzzy coating of fine hairs tastes the best. The bigger ones also taste pretty good but if you have a choice just keep in mind that the smaller fuzzy ones taste better.
Soak black-eyed peas in water for about 6 hours or overnight.
Put the black-eyed peas along with 3 cups of water in an instant pot or pressure cooker. Press "Bean" setting on an instant pot or 7 mins high pressure in an electric cooker or 4-5 whistles in a pressure cooker.
Meanwhile, peel, deseed, and slice the ash gourd into chunky pieces like in the image.
Cooked black-eyed peas
Now set it on simmer and add coconut milk, ash gourd, 1/2 a sprig of curry leaves, half of the green chilis and salt. Add more coconut milk for a richer gravy.
When the ash gourd is cooked turn off the heat and mix in coconut oil and the remaining curry leaves and green chilis. Enjoy with rice or as soup.