Mash the banana in a medium bowl until smooth with minimal lumps.

Combine wet ingredients: Add egg, milk, and vanilla to mashed banana and whisk until frothy.

Mix in dry ingredients: Gradually sprinkle flour, baking powder, and cinnamon into the wet mixture.

Heat a nonstick skillet over medium-low and coat with butter.

Cook the pancakes: Spoon batter onto the skillet and cook until bubbles form, then flip.

Cool slightly before serving, either plain or with fruit puree.