In a medium bowl, whisk together the flour, sugar, baking powder, and salt.

In a separate bowl, whisk the egg, milk, melted butter, and vanilla extract until well combined.

Pour the wet ingredients into the dry ingredients and stir until just combined.

Heat a non-stick skillet or griddle over medium heat and lightly grease with butter.

Using a fork, dip each banana slice into the batter until fully coated and place on the hot skillet.

Cook for 2 minutes per side until golden brown and the batter is set.