In a bowl, whisk together the mashed bananas, egg, buttermilk, and vanilla extract until well combined.
In a separate bowl, mix the flour, sugar, baking powder, baking soda, salt, and ground cinnamon.
Gradually fold the dry ingredients into the wet ingredients until just combined. Be careful not to overmix; a few lumps are fine.
Heat a skillet or griddle over medium heat and add a small amount of butter or oil.
Pour 1/4 cup of the pancake batter onto the skillet for each pancake. Cook until bubbles form on the surface, then carefully flip and cook the other side until golden brown.