For the Cupcakes:

1. Preheat the oven to 350°F. Line 2 and 1/2 muffin tins with cupcake liners; set aside.
2. In a large bowl, combine the flours, baking powder, baking soda, and salt; set aside.
3. In a measuring cup, combine the buttermilk and vanilla; set aside.
4. In the bowl of an electric mixer fitted with the paddle attachment, cream together the butter and sugar for 8 minutes, until smooth and creamy.
5. Add in the eggs and beat until combined, scraping the bowl down after. Add in the bananas and beat until combined.
6. On the lowest speed, alternately add in the flour mixture and buttermilk mixture, beginning and ending with the flour.
7. Scrape the bowl and stir until smooth. Allow the batter to rest for 15 minutes.
8. Fill the cupcake liners 3/4 of the way full.
9. Bake for 18 minutes, then allow them to cool for 5 minutes in the tins before removing to a wire cooling rack to cool completely.

For the Frosting:

1. In the bowl of an electric mixer fitted with the paddle attachment, beat together the cream cheese and butter until smooth.
2. Add in the confectioners’ sugar and beat on high speed for 8 minutes, until light and fluffy.
3. Add in the Nutella and salt and beat until combined. Use a rubber spatula to scrape the bowl and ensure everything is mixed.
4. Transfer the frosting to a pastry bag or large Ziploc with the end snipped off.
5. Pipe onto your cooled cupcakes!