In a large bowl, whisk to combine the all-purpose flour, granulated sugar, baking powder, salt, and ground cinnamon.

In a small mixing bowl, whisk to combine the whole milk, eggs, vanilla extract, and lemon juice.

Make a well in the dry ingredients and pour in the wet ingredients. Add the melted butter, then stir to combine until no dry streaks of flour remain. Gently fold in the finely diced apples until just combined.

If necessary, preheat your air fryer to 375°F (190°C). Line the basket of an air fryer with parchment paper and spray it with nonstick cooking spray.

Scoop 4, leveled, ¼ cup portions of batter onto the prepared parchment paper in the air fryer basket, ensuring they are not touching.

Air fry at 375°F (190°C) for 8 minutes until golden brown. Carefully flip each fritter and cook for an additional 3 minutes to ensure even cooking and a crispy bottom. Transfer the fritters to a wire rack set over a sheet tray to cool. Repeat with the remaining batter in batches. Let them cool slightly before serving.