Combine the Dry Ingredients: In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, ground cinnamon, and salt. Mix well to distribute the cinnamon and leavening ingredients evenly.
Mix the Wet Ingredients: In a separate bowl, whisk the egg, buttermilk, melted butter, and vanilla extract until smooth. Make sure the melted butter has cooled slightly before adding it.
Prepare the Pancake Batter: Pour the wet ingredients into the dry mixture. Stir gently with a spatula or whisk until just combined. A few small lumps are fine, so avoid overmixing the batter.
Heat the Skillet: Place a nonstick skillet or griddle over medium-low to medium heat. Lightly grease the surface with butter or oil and allow it to heat evenly.
Cook the Pancakes: Pour about 1/4 cup of batter onto the skillet for each pancake. Cook for 2–3 minutes, until bubbles form on the surface and the edges begin to look set.
Flip and Finish Cooking: Flip the pancakes carefully with a spatula. Cook for another 1–2 minutes, until the second side is golden brown and the centers are cooked through. Transfer the finished pancakes to a plate.
Prepare the Cinnamon Sugar: In a small bowl, stir together the granulated sugar and ground cinnamon. Brush each warm pancake lightly with melted butter, then sprinkle the cinnamon-sugar mixture over the top.
Stack and Serve: Arrange the pancakes in a stack and add any remaining cinnamon sugar to taste. Serve immediately with butter, maple syrup, or your favorite breakfast toppings.