Peel papaya, remove membrane and seeds, diced and set aside. Peeled the eggplant and diced small. In a saucepan big enough to fit diced eggplant add enough water to cover. (The diced eggplant will float to the top but that's fine) Bring to a boil and cook until fully cooked.
In a large heavy bottom saucepan or Dutch oven, heat coconut oil under medium heat. Add diced papaya, garlic, parsley, thyme, onions and let cook for 10 minutes stirring occasionally.
Add diced tomatoes, hot pepper if using, watercress (chopped) and cook for 7 - 10 minutes.
When the eggplant is cooked, drain and reserve water. Mash the eggplant with a potato masher and add to papaya mixture. Add hot pepper if using, season with salt and pepper to taste, add lemon juice and oyster sauce if using and let cook for about 3 – 5 minutes. Add about 2 cups of the eggplant water, lower heat and let cook for about 35 – 45 until fully cooked and water has decreased a lot. In the last few minutes of cooking add lemon zest. Serve hot with rice or root vegetables.