Whisk together the flour, baking powder and sea salt in a large bowl.
Add the coconut milk, water and maple syrup. Mix well.
Add the banana, if using.
If the batter is too thick, add 1 tbsp of water at a time until you get the right consistency.
Heat a waffle maker to medium-high and coat the plates with a little butter.
Pour ¼ to ½ cup of batter onto the waffle maker.
Cook for about 5 minutes or until ready.
Serve warm. Leftovers freeze well and you can reheat them in the toaster.