Prep the filling: In a bowl, combine blueberries, granulated sugar, cornstarch, lemon zest, vanilla, and salt. If your berries are very tart, add the lemon juice too. Gently stir to coat without crushing the fruit.

Chill briefly: Let the mixture sit for 5–10 minutes. This helps the sugar draw out some juices and the cornstarch start to hydrate.

Roll and cut the dough: Lightly flour your surface. Unroll the pie dough and, if needed, roll it slightly thinner (about 1/8 inch). Use a 4–5 inch round cutter or a bowl to cut circles. Gather scraps, re-roll once, and cut more.

Fill the pies: Spoon about 1–2 tablespoons of the blueberry mixture onto the center of each circle. Don’t overfill—leave a 1/2-inch border.

Seal well: Brush the edges lightly with the egg wash. Fold the dough over to make a half-moon. Press the edges together, then crimp with a fork to seal. This prevents leaks.

Vent and glaze: Cut 2–3 small slits on top of each pie to let steam escape. Brush the tops with more egg wash and sprinkle with coarse sugar for crunch.

Preheat the air fryer: Set to 350°F (175°C) for 3 minutes. Lightly spray or brush the basket with oil to prevent sticking.

Cook in batches: Arrange pies in a single layer with space between them. Air fry for 10–13 minutes, until deep golden and crisp. Rotate the basket or flip the pies at the 7-minute mark if your air fryer browns unevenly.

Cool before glazing: Let pies rest on a rack for 10 minutes. If using the optional glaze, whisk powdered sugar, milk, and vanilla until smooth and drizzle over the warm pies.

Serve: Enjoy warm as-is, or add a scoop of vanilla ice cream for dessert.