Prepare the Apples: Peel the apples and slice them into 1/4-inch thick rings. Remove the cores using a small round cutter to create rings.

Mix the Batter: In a medium bowl, whisk together the flour, sugar, salt, baking powder, and ground cinnamon. In another bowl, beat the egg and then add the milk. Mix well. Gradually add the wet ingredients to the dry ingredients, stirring until a smooth batter forms.

Preheat Oil: In a deep frying pan or pot, heat vegetable oil to 350°F (175°C).

Fry the Apple Rings: Dip each apple ring into the batter, allowing the excess to drip off. Carefully place the rings into the hot oil. Fry a few at a time, making sure not to overcrowd the pan. Fry the rings for about 2-3 minutes on each side or until golden brown. Remove and drain on paper towels.

Coat with Cinnamon Sugar: In a shallow dish, combine the granulated sugar and ground cinnamon. While still warm, toss the apple rings in the cinnamon sugar until evenly coated.