Combine apples and ½ teaspoon cinnamon in a bowl and toss until coated. Set aside.

In a large bowl, combine flour, sugars, baking powder, remaining ½ teaspoon cinnamon, and salt; whisk until well-combined.

In a separate bowl, beat eggs until pale yellow and frothy. Add milk and vanilla extract; whisk together.

Slowly pour melted butter into the wet ingredients while whisking until well-combined.

Pour wet ingredients into dry ingredients and fold together until halfway combined. Add cinnamon-coated apple pieces and continue to fold until just combined.

Fill a Dutch oven or large saucepan 2-3 inches deep with oil for frying. Attach a candy thermometer and heat oil to 360-365°F (175-185°C).

While oil is heating, prepare the glaze by whisking together powdered sugar, apple cider, and vanilla extract until smooth. Set aside.

Once the oil has reached temperature, scoop about 3 tablespoons of batter and carefully drop into the oil. Repeat with 2 more scoops.

Fry each fritter for 60-75 seconds on each side, or until golden brown.

Use tongs to remove fritters to a paper-towel-lined plate and allow to cool briefly before dipping in glaze and transferring to a cooling rack to set.

Enjoy fritters warm the same day for best quality.