Soak the cowpeas in a bowl of water overnight.
The next day, drain, rinse and put the cowpeas in the pressure cooker. Cook under pressure for 10 minutes. Alternatively, cook in a large pan of water for 1-1 1/2 hours, or until soft.
Bring a large pan of water to a boil and add the ash gourd, chillies, and 10 curry leaves. Season with salt and cook for about 30 minutes. Drain and allow to cool in a bowl, then mash with a wooden spatula or potato masher.
Mix in the cowpeas and add coconut milk. Transfer to a clean pan and simmer for 2 minutes.
Heat the oil in a small frying pan (skillet) over high heat. Reduce the heat, add the remaining curry leaves, and stir-fry for about 30 seconds, or until they change color. Pour over the ash gourd mixture.