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, large egg, melted unsalted butter, and vanilla extract. Whisk until smooth.
Add the wet ingredients to the dry ingredients and stir gently until just combined. Do not overmix; some lumps are okay.
Fold the mashed ripe bananas into the batter carefully.
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 2-3 minutes.
Flip the pancakes and cook for another 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 or fresh fruit.