In a large mixing bowl, whisk together all-purpose flour, baking powder, ground cinnamon, ground nutmeg, salt, and granulated sugar until well combined.

In a separate bowl, whisk together egg, milk, melted unsalted butter, and vanilla extract until smooth.

Carefully pour the wet mixture into the dry ingredients and gently fold until just combined.

Fold in the diced apple until evenly distributed.

Let the batter rest for about 5-10 minutes.

Heat a lightly oiled griddle or non-stick skillet over medium heat.

Pour 1/4 cup of batter onto the hot surface and cook until bubbles form, about 2-3 minutes.

Flip the pancake and cook until golden brown, another 2-3 minutes.

Transfer pancakes to a plate and serve warm with optional toppings.