In a large mixing bowl, combine the flour, sugar, baking powder, baking soda, and salt.
Give it a good stir until everything is well mixed.
Whisk your egg, buttermilk, and vanilla in a separate bowl.
Slowly pour this mixture into the dry ingredients.
Mix gently until the batter is smooth without over-mixing.
Mix cinnamon and brown sugar in a small bowl for the cinnamon filling.
Set this aside for now.
Preheat your griddle or non-stick pan to medium heat.
Add a little vegetable oil or butter to coat the surface evenly.
Pour about ¼ cup of batter onto the heated pan for each pancake.
Sprinkle a layer of the prepared cinnamon mixture over the top.
Cook until bubbles form on the surface, then flip.
Serve warm with a pat of butter.