Whisk flour, brown sugar, cinnamon, apple pie spice, and salt together in a medium bowl.
Add milk, egg, butter, and vanilla together. Stir just to mix well.
Pour the milk mixture into the bowl with the dry ingredients.
Stir just to combine the ingredients. (Do not over stir.)
The mixture will have lumps.
Gently add the grated apple. Do not over mix.
Add the butter to your skillet over medium heat. Allow the butter to melt.
Using a 1/4 C measure, scoop out pancake batter.
Pour the batter onto the hot skillet.
Cooking for up to 1-2 minutes.
The batter will have small bubbles.
Flip the pancakes to cook the other side. Lower the heat to low-medium cooking for about 1 minute. (You can use a toothpick in the center of the pancake to make sure that it is done.)
Place the pancakes on a parchment lined baking sheet in a 200-degree oven to keep warm.)