1cupmashed bananafrom approximately 2 large or 3 medium overripe bananas
½cupGreek yogurt OR sour creamat room temperature
For the Cinnamon Sugar Coating:
For the Chocolate Glaze:
3tablespoonsbuttersalted or unsalted
1 ½tablespoonslight corn syrup
½teaspoonpure vanilla extract
Adjust oven racks to center position and preheat oven to 425°F. Spray two 6-cavity donut pans with nonstick cooking spray and set aside.
In a large bowl, whisk together flour, baking soda, and salt. In another bowl, use an electric mixer to beat the butter until smooth, and then beat in the sugar until light and fluffy. Blend in the egg, vanilla, mashed bananas, and sour cream until fully incorporated (batter may look curdled at this point...it will smooth out with addition of flour). Gently mix in the dry ingredients until just blended. Evenly divide the batter between the prepared donut pans.
Bake for 7 to 9 minutes until the tops of the donuts spring back when lightly touched. Allow donuts to cool for 5 minutes in pans before turning them out onto a cooling rack.
FOR THE CINNAMON SUGAR COATING: In a medium bowl, combine the sugar and cinnamon. Place the melted butter in a shallow bowl. Dip one side of each donut in the butter, and then press into the cinnamon sugar. Serve warm or at room temperature.
FOR THE CHOCOLATE GLAZE: Place a small saucepan over medium-low heat and melt together the butter and corn syrup. Remove the pot from the heat and add the chocolate chips, stirring until they are smooth and completely melted. Stir in the vanilla. If necessary, transfer to a bowl for dipping (or you can dip the donuts directly into the pot). While the glaze is still warm and thin, dip one face of each donut into the glaze. Place glaze-side-up on a plate or cooling rack. For optimal flavor and texture, serve sooner than later.