Peel the apples and cut them into small, evenly sized chunks. Toss the pieces with the cinnamon-sugar mixture so the fruit gets an even coating. Keeping the chunks similar in size helps the apples cook consistently inside the fritters.
Add the flour, sugar, salt, and baking powder to a mixing bowl. Whisk everything together until the dry ingredients are evenly distributed. This creates the simple base for the fritter batter.
In a separate small bowl, whisk the milk and egg until combined. Pour this mixture into the dry ingredients. Stir only until everything is incorporated; avoid unnecessarily overmixing the batter.
Add the cinnamon-sugar-coated apple pieces to the batter. Give the mixture a gentle stir so the apples are distributed throughout without aggressively mixing the batter. Try to make sure every portion you scoop contains a good amount of apple.
Heat the frying oil to 370°F before adding the batter. Getting the oil to the right temperature is important for developing that golden exterior while cooking the inside properly. I recommend having your draining setup ready before you begin frying.
Drop heaping spoonfuls of batter into the hot oil, using a small cookie scoop if you have one. Fry the fritters for about 2–3 minutes, or until they become golden brown. For the best results, fry only three or four at a time rather than overcrowding the pot.
If you are using an open pot or pan, carefully turn the fritters with a spatula or fork. This allows the sides to cook evenly and develop that appealing golden color. I would fry one fritter first so I can judge the cooking time before making the rest.
Remove the finished fritters and place them on a cooling rack with paper towels underneath. If you want cinnamon sugar on the outside, coat the fritters while they are still warm enough to handle. For powdered sugar or glaze, let them cool slightly before finishing.
For a simple glaze, combine powdered sugar with vanilla and 1–1½ tablespoons of milk. Stir until smooth, adding only enough liquid to create the consistency you want. Drizzle the glaze over the fritters or dip them into it, then allow them to set briefly.