In a large bowl mash, the bananas then add the 1/3 cup melted butter, eggs, sugar, and vanilla.
In a smaller bowl whisk together the flours, baking soda, salt, and teaspoon of cinnamon.
Add about half of the dry ingredients to the wet, stir, then add the rest.
Preheat the oven to 350°F and grease a silicone donut baking dish
Spoon the banana batter into the donut molds and bake for 12-25 minutes or until golden.
Let cool slightly and before placing them on a wire rack. While they are still warm, dip the donuts into melted butter and then into the cinnamon sugar mixture (2 tablespoons cinnamon to 1/4 cup sugar)