In a blender, combine one of the bananas, eggs, milk, coconut flakes (reserve a couple of tablespoons for topping), sugar and cinnamon. Pulse until well blended. Pour this mixture into a large shallow bowl. Let the mixture settle for 5 minutes before using.
Heat a griddle over medium heat. Spray with cooking spray.
Dip each piece of bread in the liquid mixture, making sure to coat both sides completely.
Transfer to the griddle.
Cook until the underside is golden brown (about 4 minutes). Flip and cook other side until golden brown (about 3 minutes).
Slice remaining banana. Top french toast with yogurt, banana slices and remaining coconut flakes.