Preheat oven to 350 degrees F. Lightly coat an 8×8 baking dish with nonstick spray.

In a large bowl, combine flour, cinnamon, baking powder, baking soda and salt.

In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium-high until light and fluffy, about 2-3 minutes. Beat in egg and vanilla until well combined.

With the mixer on low speed, add buttermilk and dry ingredients alternately in 3 parts, beginning and ending with the dry ingredients, beating just until incorporated. Beat in bananas until well combined.

Scoop the batter evenly into prepared baking dish. Top with Nutella, swirling into the batter using figure eight motions. Sprinkle with pecans, using your fingertips to gently press the pecans into the batter.

Place into oven and bake for 30-35 minutes, or until a tester inserted in the center comes out clean. Let cool slightly before cutting into bars.