Start by peeling and finely dicing the apples into small, even pieces.
2½ cups apples
In a skillet over medium-low heat, combine the diced apples, butter, brown sugar, cinnamon, nutmeg, and cornstarch. Stir occasionally and let the mixture simmer for 5-7 minutes, or until the apples are soft and the mixture has thickened. Remove from the heat and allow the filling to cool slightly.
1 tablespoon unsalted butter, ½ cup packed brown sugar, 1½ teaspoons cinnamon, ¼ teaspoon nutmeg, 1 tablespoon cornstarch
Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Once thawed, roll out one sheet of puff pastry on a lightly floured surface into a rectangle (approximately 15 x 10 inches / 38 x 25 cm). Cut the pastry into 6 equal squares. Repeat with the second sheet.
17.25 ounces frozen puff pastry
In a small bowl, whisk together the egg and water to create an egg wash. Brush the edges of each pastry square lightly with the egg wash.
1 large egg, 1 tablespoon water
Spoon about 2 tablespoons of the apple filling into the center of each square. Fold the pastry over diagonally to form a triangle. Press the edges together and use a fork to crimp and seal.
Place the turnovers onto the prepared baking sheet. Brush the tops with more egg wash and use a sharp knife to cut a small slit in each one to allow steam to escape.
Bake for 18-20 minutes, or until the turnovers are golden, puffed, and crisp.
Remove from the oven and allow to cool for 10-15 minutes on a wire rack.
To make the glaze, mix the powdered sugar with 1-2 tablespoons of milk until smooth. Adjust the consistency as needed, then drizzle over the slightly cooled turnovers before serving.
½ cup powdered sugar, 1-2 tablespoons milk
Notes
Tips and Tricks
Cool the filling first. Warm filling can melt the pastry and make it harder to work with.
Don’t overfill. Too much filling can cause the turnovers to leak during baking.
Seal well. Press firmly with a fork to prevent the edges from opening.
Keep pastry cold. If it becomes too soft, pop it back in the fridge for a few minutes.
Make ahead. The apple filling can be made up to 3 days in advance and stored in the fridge.
Freezer-friendly. Assemble turnovers and freeze before baking - bake straight from frozen, adding a few extra minutes.
Extra flavor. Add a splash of vanilla or a squeeze of lemon juice to the filling for extra depth.