Peel and cut up the plantains. Puree them in a blender or mash them with a potato masher.
Add the flour, milk, water, sugar, eggs, melted butter, vanilla extract, and nutmeg, and pulse several times until thoroughly mixed and smooth. Scrape the sides if needed and do one last pulse.
Let the batter rest for about 30 minutes or overnight in the refrigerator. Adjust the consistency of the batter if needed. You want it to be pourable, but not too thin.
Heat a skillet or a non-stick frying pan, and lightly coat it with vegetable oil, cooking spray, or clarified butter.
Pour in about a ½ cup of batter, depending on the size of your fry pan or skillet. Tilt the pan so the batter spreads across the bottom. Cook the pancake for about a minute on each side, or until the bottom is light brown.
Serve hot with coconut sauce, cinnamon sugar, powdered sugar, or maple syrup.