In a small bowl, mix the ground chia, water and 1/4 teaspoon of baking powder. Let sit for 15 minutes until it forms a sticky liquid.
Remove the pits from the medjool dates and chop finely. Melt the coconut oil in a bain marie.
In a large bowl mash the bananas using a spoon or fork and then add the ground chia mixture, maple syrup, vanilla essence, melted coconut oil and chopped medjool dates.
In a separate bowl, mix the flour, salt and 2 teaspoons of baking powder.
Combine together all ingredients and stir well until it becomes a smooth homogenized mixture.
Pour the mixture into muffin cups. Decorate with a banana slice and sprinkle with chia seeds.
Bake for 15 to 20 minutes, and let cool for a few minutes before taking the muffins out of the pan.