Preheat the oven to 400°F Lightly grease a baking sheet with cooking spray and set aside.
In a medium bowl, combine the flour, 1/2 cup of brown sugar, baking powder, salt, and baking soda. With a pastry blender or 2 forks, cut in the butter until the mixture resembles coarse meal.
In a separate bowl, combine the buttermilk, extract, and egg whites. Whisk together well. Add to the flour mixture along with the mashed bananas. Stir well.
The dough will be wet and sticky, but turn onto a well-floured surface and knead lightly 5 times. Pat into a 9-inch circle on the prepared baking sheet. Sprinkle with the pecans and remaining tablespoon of brown sugar, pressing gently into the dough.
With a sharp knife, cut the dough into 12 weges. **Cut into, but not all the way through, the dough.** Bake 20 minutes, or until golden brown.