Mash the banana in a separate mixing bowl; into this bowl mix the milk and vanilla extract. Pour the liquid ingredients into the dry ingredients and stir until well combined.
Heat a griddle on medium high heat. Put 1/4 cup of batter on the griddle for each pancake. When the pancake begins to bubble, turn it over and spread some peanut butter on the cooked side. Remove from griddle when cooked.
posted by Medellia12