Preheat the oven to 325 degrees.

In a large bowl, mash your bananas until smooth. Add the sugar, sour cream, melted butter, eggs and vanilla and whisk to combine.

In a separate bowl, whisk together the flour, baking powder, baking soda and salt.

Add the flour mixture to the banana mixture and fold together with a spatula until the donut batter is just combined.

Using a spoon or metal cookie scoop, divide the batter evenly among 12 donut wells (2 pans). Smooth the top of the batter with your finger.

Place 8-10 chocolate chips on top of each donut - pushing in slightly with your finger.

Bake the donuts on the middle rack of your oven for 12 - 14 minutes.

Remove the baked donuts from the oven and using a knife, lightly spread the melted chocolate chips on top of the donuts like frosting.

Allow to cool in the pans for about 10 minutes and gently remove donuts to finish cooling on a rack.

Dust with powdered sugar and serve.