Prepare the Fritter Batter:
In a large bowl, whisk together flour, sugar, baking powder, salt, and cinnamon.
In another bowl, mix milk, eggs, and melted butter.
Gradually add the wet ingredients to the dry ingredients, stirring until just combined.
Fold in the diced apples.
Heat the Oil:
Heat vegetable oil in a deep fryer or large skillet to 350°F (175°C).
Fry the Fritter Bites:
Use a cookie scoop or small spoon to drop spoonfuls of batter into the hot oil.
Fry in batches, being careful not to overcrowd the pan, until golden brown, about 2-3 minutes per side.
Use a slotted spoon to transfer the fritter bites to paper towels to drain.
Prepare the Glaze (optional):
In a small bowl, whisk together powdered sugar, milk, and vanilla extract until smooth.
Glaze the Fritter Bites:
Once the fritter bites are slightly cooled, drizzle with the glaze or dip them into the glaze.