Preheat oven to 350 degrees. Spray a 10x5x3-inch loaf pan with cooking spray and line with parchment paper.

In a medium bowl, whisk together 2 cups flour, baking soda, baking powder, and salt; set aside.

In a large bowl, using an electric hand mixer, beat sugar and butter until light and fluffy about 1-2 minutes.

Add mashed bananas, eggs, sour cream, and vanilla beat until combined. Gradually add flour mixture, beating on low speed until moist.

Place blueberries in a small bowl with 1 tablespoon flour; toss to coat.

Gently fold blueberries into the batter. Spoon batter into the prepared loaf pan. Add additional blueberries to the top of the batter for decoration.

Bake for 60-70 minutes or until a wooden spoon inserted in the center comes out clean. Tent with foil if the bread starts to get too brown on top towards the end of baking.

Cool bread for 10 minutes in the pan over a wire rack; remove the bread from the pan to cool completely. Slice, slather with butter, and devour!