In a large bowl, gently whisk oat flour, sugar, cinnamon, baking powder, baking soda, and salt.
In a separate medium bowl, mash the banana. Add the buttermilk, butter, egg, and vanilla and whisk to combine.
Add liquid ingredients to the oat mixture. Using a spatula, stir to combine. Allow batter to rest 10-15 minutes before cooking.
Heat a griddle or large non-stick pan over medium-low heat. Lightly grease with non-stick spray or a little butter. Pour ~¼ cup batter onto the griddle to create pancakes. Immediately sprinkle any desired toppings on pancakes, and gently press toppings down as needed. Cook until tiny bubbles appear on the surface and the edges start to firm up.
Flip and cook for ~2 more minutes. You might need to lower the heat as you cook additional batches. Hold in the oven on a warming setting (~170° F) until ready to eat. Enjoy!