Preheat the oven to 325 degrees. Prepare a 6 cup capacity mini bundt pan with either Baker's Joy spray or homemade cake release.

In a small mixing bowl, combine the flour, baking soda, and salt.

In a medium mixing bowl, beat the butter until light and creamy, add the sugar and beat again until fluffy. Add the egg, vanilla, and bananas mixing until well combined.

Add half the dry ingredients and the sour cream, mixing on low and finishing with the remaining dry ingredients.

Pour the cake batter into the prepared mini bundt pan, filling each cavity 2/3 full. Lightly tap the bundt pan on the counter to remove any large air bubbles.

Bake at 325 degrees for 30 minutes or until the cakes are golden brown and a toothpick inserted in the center comes out clean.

Cool on a wire rack for 10 minutes and then turn out the cakes. Cool completely.

Over low heat, melt the chocolate chips and butter together until completely melted and no lumps remain. Whisk in the Nutella and drizzle over the cakes.