Mix milk and lemon juice in a bowl and let stand for 5 minutes to make buttermilk
Whisk flour, sugar, baking powder, baking soda, cardamom, cinnamon and salt in a large bowl.
Whisk eggs, milk from step #1, and butter in a medium bowl; stir into dry ingredients until just combined (some lumps are okay).
Rest batter for 5 to 10 minutes
In the meantime, heat a small pan on medium heat.
Add 1 tablespoon butter.
Once butter has melted, add the apple, cinnamon, salt, and sugar.
Cook on medium heat, constantly stirring for about 10 minutes to caramelize the apple. Set aside.
Heat a griddle or large skillet over medium; brush with oil. Working in batches, scoop ⅓-cupfuls of batter onto griddle. Cook pancakes until bottoms are golden brown and bubbles form on top, about 3 minutes. Flip and cook until cooked through and both sides of pancakes are golden brown, about 2 minutes longer.
Stack 2 or 3 pancakes and top each stack with apple pie filling and maple syrup (if using).
Serve and enjoy!