In a medium bowl, whisk together the flour, oats, baking powder, cinnamon, baking soda, and salt. Set aside.

In a large bowl, combine the mashed bananas, buttermilk, granulated sugar, brown sugar, oil, eggs, and vanilla extract.

Add the dry ingredients and stir with a spatula until just combined. Do not over mix. You want there to be a few flour streaks left. The batter will be thick. If you want to stir in chocolate chips, do it now. Cover the bowl with a clean dish towel and let the batter sit at room temperature for 30 minutes.

While the batter is resting, preheat the oven to 425 degrees F. Line 2 muffin pans with paper liners, leaving a space in between every cup. This will help the muffins rise higher in the oven. Spray the liners with nonstick cooking spray.

Divide the muffin batter evenly among the muffin cups, filling to the top. I like to use a large ice cream scoop. Sprinkle the tops with oats and turbinado sugar.

Bake the muffins on the center rack for 5 minutes at 425 degrees, then turn the oven down to 350 degrees. Do not open the oven door. Bake for an additional 8 to 12 minutes or until the muffin tops are golden and the tops are set. You can insert a toothpick into the center of a muffin and if it comes out clean, they are done. Don’t over bake.

Transfer the pan to a cooling rack and let the muffins cool for 5 minutes in the pan. Remove from the pan and enjoy!