Preheat oven to 350 degrees. Spray a 9 x 5-inch loaf pan with nonstick cooking spray.
Mix butter and sugar until light and fluffy, using a stand mixer or hand mixer.
Add eggs and vanilla; mix until fully incorporated.
Stir in bananas by hand.
Using a separate bowl, whisk together 1 ½ cups flour, salt, baking soda, and baking powder.
Gently fold flour into butter mixture. Do not overmix; there should still be a little flour visible when you are done.
In a separate bowl, stir together 1 tablespoon flour and blueberries.
Add blueberries to batter, then gently fold in with a spatula.
Transfer batter to loaf pan. Bake for about 50 to 55 minutes, or until a toothpick inserted in the center comes out mostly clean.
Cool bread before slicing. Enjoy!
Notes
When measuring the flour, make sure to spoon it into the measuring cup, then level off the top with a flat knife. Avoid scooping the measuring cup into the flour; this will compact the flour, and you'll end up adding too much.The key to making the BEST quick breads is to avoid over-mixing the batter. Always use a spatula to fold (not stir) the wet and dry ingredients together. And don't worry if there's a spot or two of flour showing when you're done. Make sure to allow your bananas to turn brown before making this bread.Baking time can vary depending on your oven. I usually start checking the bread at about 45 minutes, just to be on the safe side.For a prettier loaf, reserve a few blueberries before mixing them with the flour. After you add the batter to the pan, sprinkle them evenly over the top before baking.Check out the info before this recipe card for helpful tips, recipe variations, and more!