Preheat the oven to 350℉. Lightly spray donut pans with cooking spray and set aside.
In a medium bowl, mix together the flour, baking powder, baking soda and salt. Set aside.
In a large bowl, cream together the sugars and maple syrup until combined. Mix in the eggs, oil, bananas, yogurt and vanilla until smooth.
Slowly mix the dry ingredients into the wet ingredients until just combined.
Scoop the batter into a large ziplock bag and cut the tip off. Fill each donut cavity around 3/4 full.
Bake in the preheated oven for around 15 minutes, or until a toothpick inserted comes out clean. Allow to cool in the pan for around 5 minutes, then transfer to wire racks to cool completely.
Cinnamon sugar: In a small bowl, mix together the sugar and cinnamon. Dip each donut in the melted butter, then dip the donut into the cinnamon sugar, making sure to coat both sides.