Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the flour, baking powder, cinnamon, nutmeg, salt, and granulated sugar. Whisk until well blended.
In a separate bowl, mix together the milk, egg, vanilla extract, and melted butter until smooth.
Add the wet ingredients to the dry ingredients and mix until just combined. Be careful not to overmix.
Fold in the diced apples gently using a rubber spatula.
Drop tablespoonfuls of the batter onto the prepared baking sheet, leaving space between each fritter.
Bake in the preheated oven for about 20 minutes, or until the fritters are golden brown and cooked through.
While the fritters are baking, prepare the glaze by whisking together the powdered sugar and 2 tablespoons of milk until smooth. Adjust consistency if necessary by adding more milk or powdered sugar.
Once the fritters are done, remove them from the oven and let them cool slightly. Drizzle the glaze over the warm fritters.
Optional: Sprinkle with additional cinnamon if desired.