Add the vanilla and sugar to the banana mixture. Whisk well to combine.
To the same bowl, fold in the oats, oat flour, cinnamon, baking soda, and salt using a spatula. Add the blueberries. Fold only until no dry spots remain. Do not overmix.
Add the batter to a greased 9x9 baking dish.
Bake in a preheated oven for 30-35 minutes until a toothpick inserted into the center of the bars comes out clean.
Remove from the oven and allow to cool completely before slicing into 9 bars.
Notes
For added protein, serve each bar with a heaping spoonful of Greek yogurt and a drizzle of maple syrup.