Preheat oven to 350 F. Grease donut pan and set aside.
Add brown sugar, granulated sugar and butter to the bowl of a stand mixer. Using the paddle attachment, cream together the sugars and butter.
Add egg and continue to mix until just incorporated
Add the whole wheat flour, cinnamon, baking powder, fine sea salt and sourdough discard. Mix on a low speed until fully incorporated being sure to scrape down the sides of the bowl, as needed.
Add bananas and continue mixing on a low speed until the bananas have been broken down into small chunks. Alternatively, if you prefer continue mixing until the bananas have fully disappeared into the mixture. Once the mixture has reached your preferred consistency add pecans and chia seeds, if using, and fold them into the dough mixture.
Fill each individual donut mold roughly 2/3 of the way full (about 3 tbsps) with the banana bread mixture. Bake for 12 to 14 minutes until firm and lightly browned, or until a toothpick comes out clean. Once the baking time as lapsed remove the donut pan from the oven and although the donuts to cool in the pan for 5 to 10 minutes before transferring to a cooling rack to allow them to cool completely. Repeat with any remaining batter until all donuts have been baked.