In a large bowl, mix flour, baking powder, salt, and cinnamon together.

In another bowl, whisk eggs, brown sugar, and vanilla until combined.

Pour the egg mixture into the flour mixture, stirring until smooth. Add the milk and mix well.

Gently fold in the diced apples until they are just coated. Be careful not to overmix.

Fill a Dutch oven or cast-iron pot with at least 2 inches of vegetable oil and heat it on medium-high until the temperature reaches 350°F.

Scoop the batter using a tablespoon or a cookie scoop and drop it into the hot oil. Fry 3-4 fritters at a time, cooking for about 2 minutes on each side, until they are deep golden brown.

Use a spider tool to remove the fritters from the oil and place them on a tray lined with paper towels to drain excess oil.

Prepare the glaze by mixing powdered sugar, water, and vanilla extract. Dip each fritter in the glaze and set aside to cool slightly.