Creating these delightful Cinnamon Sugar Banana Bread Donuts is straightforward when you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C) and grease your donut pan with cooking spray or butter.
2. Mix Wet Ingredients: In a large bowl, mix the mashed bananas, granulated sugar, softened butter, eggs, vanilla extract, and buttermilk until well combined.
3. Combine Dry Ingredients: In another bowl, whisk together the flour, baking powder, baking soda, ground cinnamon, and salt.
4. Combine Mixtures: Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix; lumps are perfectly fine!
5. Fill the Pan: Using a piping bag or a spoon, fill each cavity of the donut pan about two-thirds full with the batter.
6. Bake: Place the filled donut pan in the preheated oven and bake for 20-25 minutes or until a toothpick inserted comes out clean.
7. Cool the Donuts: Allow the donuts to cool in the pan for 5 minutes, then carefully transfer them to a wire rack to cool completely.
8. Prepare Cinnamon Sugar Coating: In a shallow dish, mix together the granulated sugar and ground cinnamon.
9. Coat the Donuts: Once the donuts are cool, roll them in the cinnamon sugar mixture until completely coated.
10. Serve and Enjoy: Your Cinnamon Sugar Banana Bread Donuts are now ready to be served!