Preheat oven to 350-degrees.
Spray a muffin tin with baking spray. Set aside.
**Note - Muffin liners may be used, but they aren't necessary.
Toss the blueberries with 1 tablespoon flour and set aside.
In a small bowl, stir together the milk and lemon juice (if NOT using buttermilk). Set aside for 2-3 minutes.
In a large bowl, whisk together the mashed bananas, buttermilk OR buttermilk substitute, eggs, oil, brown sugar, vanilla, and lemon zest.
In a medium bowl, whisk together the 2½ cups all-purpose flour, baking soda, baking powder, and salt.
Add the dry ingredients into the wet, banana mixture and stir gently.
Add the flour-coated blueberries to the muffin batter and gently fold them into the batter just until the blueberries are incorporated. Do not overmix.
Use an ice-cream scoop or large spoon to fill the muffin tins 3/4's full with the muffin batter.
Bake in a preheated oven for 25-30 minutes, or until the muffins are golden and when a toothpick inserted in the center comes out clean.
Cool for 10 minutes, and then run a knife around each muffin to loosen them from the tin.
Turn all the muffins out onto a cooling rack and cool completely.
Tools and equipment;
muffin tin, muffin liners (optional), baking spray, large bowl, medium bowl, whisk, wooden spoon, fork or pastry blender (for mashing bananas), small bowls, measuring cups, measuring spoons.