Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, salt, cinnamon, and nutmeg.
In another bowl, whisk together the milk, eggs, and vanilla extract until well combined.
Pour the wet ingredients into the dry ingredients and mix until just combined, then fold in the diced apples and melted butter until evenly distributed.
Using a large spoon or ice cream scoop, drop mounds of batter onto the prepared baking sheet, spacing them a few inches apart.
Bake in the preheated oven for 15-18 minutes, or until the fritters are golden brown and a toothpick inserted into the center comes out clean.
While the fritters are baking, whisk together the powdered sugar, milk, and vanilla extract in a small bowl until smooth.
Remove the fritters from the oven and let them cool slightly on a wire rack, then drizzle the glaze over the warm fritters.