Preheat the oven to 375° and have ready two greased muffin tins, greased or lined with cupcake liners. Melt the butter and set aside to cool until lukewarm or at room temperature. Toss the blueberries with 2 tablespoons of flour and set aside.
In a medium-sized mixing bowl, combine 2 ¼ cup flour, baking powder, baking soda, and salt. Whisk to combine. Set aside until ready to use.
In a large mixing bowl, whisk together cooled butter, bananas, sugar, egg, and vanilla until well blended.
Stir in the dry ingredients to the wet in three additions, alternating with the buttermilk, until all of the ingredients have been combined. Add the flour-coated blueberries and stir until evenly dispersed.
Fill the muffin tins ⅔'s of the way full and bake for 18-20 minutes, until the muffins are golden brown and a toothpick inserted in the center comes out moist, but not wet with batter. Allow to cool slightly, serve, and enjoy.
Notes
Consider using parchment paper muffin liners. If you don't have this kind, it's best to spray the muffin liners and the pan with cooking spray before adding the batter.Makes 16 muffins.