Preheat vegetable oil in a large, deep pot to 375°F (190°C). Use a kitchen thermometer to monitor the temperature.

In a large mixing bowl, combine all-purpose flour, baking powder, cinnamon, and salt. Whisk until well-blended.

In a separate bowl, whisk together eggs, granulated sugar, melted unsalted butter, whole milk, and vanilla extract until smooth.

Gently pour the wet mixture into the dry ingredients and stir until just combined. Toss blueberries with flour, then fold into the batter.

Drop generous amounts of batter into the hot oil, frying each fritter for 2-3 minutes on each side until golden brown.

Prepare the glaze by whisking together powdered sugar, light corn syrup, a pinch of salt, vanilla extract, and water until smooth.

Dip each fritter into the glaze or brush it over the top. Allow glaze to set before serving.