In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, baking soda, and salt.
In a separate medium bowl, combine the buttermilk, egg, melted unsalted butter, and vanilla extract. Whisk until smooth.
Add the wet ingredients to the dry ingredients and gently stir until just combined. Do not overmix; the batter should be slightly lumpy.
Fold the mashed ripe bananas into the batter until evenly distributed.
Heat a non-stick skillet or griddle over medium heat and lightly grease with butter or oil.
Pour 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface and the edges look set, about 2 to 3 minutes.
Flip the pancakes and cook for an additional 2 minutes or until golden brown and cooked through.
Transfer the cooked pancakes to a plate and keep warm. Repeat with the remaining batter, greasing the skillet as needed.
Serve the fluffy banana pancakes warm with your favorite toppings such as maple syrup, sliced bananas, or nuts.