In a large bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and sugar.
In a separate bowl, beat the egg and mix in the buttermilk, melted butter, and vanilla.
Add the wet ingredients to the dry ingredients and stir gently until just combined. A few lumps are fine.
Fold in the grated apple.
Heat a non-stick skillet or griddle over medium heat and grease with butter or oil.
Pour about 1/4 cup of batter for each pancake. Cook for 2–3 minutes, until bubbles form on top, then flip and cook another 1–2 minutes.
Repeat with the remaining batter.
Serve warm with maple syrup, extra apple slices, or a dusting of cinnamon sugar.