Preheat the oven to 400° degrees and prepare a 12 cupcake pan by adding liners. Add a spritz of nonstick cooking spray to the liners.
In a large mixing bowl, add the flour, baking soda, baking powder, spices and salt. Whisk together to combine.
Add the buttermilk, melted butter, mashed bananas, sugar and vanilla to the dry ingredient mixture. Mix everything together until combined. Do not over mix.
Add the walnuts and fold into the batter.
Divide the batter evenly among the cupcake liners filling each approximately ¾ full.
Bake the cupcakes at 400° degrees for the first five minutes.
Then reduce the oven temperature to 350° degrees and continue to bake for an additional 15-20 minutes or until a toothpick inserted in the center of a cupcake comes out clean without batter.
Times may vary depending on your oven, so watch the cupcakes carefully and check often starting at the 14-minute mark.
Remove the cupcakes to a rack to cool completely before frosting.
Let them cool COMPLETELY before frosting.