for batter:
Mix buttermilk, eggs, vanilla.
Sift or whisk together flour and cinnamon.
Add to wet mixture and stir lightly.
Add brown sugar and stir.
Peel, core, and dice each apple separately, adding each to the batter as soon as they are diced. Stir after each addition. Coating each freshly diced apple with the batter quickly helps them to keep from turning brown.
Add 2 inches of cooking oil to a a sturdy cooking vessel that's appropriate for deep frying. Preheat to 350 degrees.
Cooking in batches, drop tablespoons of batter in the hot grease. Don't crowd them. As soon as the edges are brown, flip the batter and fry until that side is browned. Flip every 20 seconds, or so, until both sides are golden brown.
Removed to a paper towel lined tray or dish.
Repeat in batches until all batter is fried.
for glaze:
Mix all glaze ingredients until smooth.
for glazed apple fritters:
Add each fritter to the glaze mixture and turn to coat.
Place glazed fritters on a wire rack.
optional: dust each glazed fritter with powdered sugar