1. In a mixing bowl, add mashed banana, baking soda, baking powder, salt, vanilla extract and the egg, then whisk until well combined. Let set for a couple minutes.
2. Add melted butter and milk and stir.
3. Add flour and stir until just combined. If your batter appears too thin, add a bit more flour, or if too thick, add milk. Let the batter rest for 5 minutes.
4. Lightly grease your griddle and pour 1/4-cup of the batter onto the griddle.
5. Cook until bubbles start to appear and flip the pancake, then cook for about a minute.