Preheat the oven to 375°F and line a baking sheet with parchment.
Sauté the diced apples with butter and brown sugar until soft and caramelized.
In a bowl, whisk flour, sugar, baking powder, cinnamon, nutmeg, and salt.
In another bowl, whisk the egg, milk, and vanilla until smooth.
Pour the wet mixture into the dry and stir gently until just combined.
Fold the warm apples into the batter so every scoop has fruit.
Drop small mounds of batter onto the baking sheet, leaving space between them.
Bake for 12–15 minutes until the tops look golden and lightly crisp.
Whisk powdered sugar, milk, and vanilla until smooth. Drizzle glaze over the warm fritters and allow it to set slightly before serving.