Mix dry: In a medium bowl whisk flour, sugar, baking powder, baking soda, salt, and apple pie spice.
Add wet: Whisk egg, buttermilk, melted butter, and vanilla until just combined. Batter should be thick with small lumps.
Fold in apples: Gently fold in diced apple. If batter seems too thick, splash in 1-2 tbsp more milk.
Cook: Heat a lightly oiled skillet over medium heat. Scoop 1/4 cup batter per pancake. Cook 2-3 minutes until bubbles form and edges look set, flip, then cook 1-2 minutes more.
Serve: Stack warm with maple syrup and your favorite toppings.