In a medium saucepan, combine the canned peaches, thawed mango, peach syrup, brown sugar, cinnamon, and salt over medium heat. Gently mash the fruits as they begin to warm up, allowing the juices to release. Cook for about 20 minutes until the mixture thickens, stirring occasionally. Afterward, add a cornstarch slurry and cook for an additional 2-3 minutes until glossy before removing from heat. Stir in the vanilla extract and let it cool completely.

While the filling cools, preheat your oven to 375°F (190°C). Roll out the puff pastry on a lightly floured surface until it’s about 1/8 inch thick. Using a round cutter, cut the pastry into circles about 4 inches in diameter. Line a baking sheet with parchment paper and lay half of the pastry circles on the sheet, ensuring there’s some space between each.

Spoon 1-2 tablespoons of the cooled peach mango filling into the center of each pastry circle on the baking sheet. Carefully place the remaining pastry circles on top of the filled ones, pressing down gently. Use a fork to crimp the edges securely, ensuring no filling escapes during baking. Remember to cut small slits in the top to allow steam to vent while they bake.

To help the pastry maintain its flakiness, place the assembled pies in the freezer for about 10-15 minutes while the oven finishes preheating.

Remove the chilled pies from the freezer, and prepare an egg wash by whisking together the egg and milk. Lightly brush the egg wash over the tops of each pie to achieve a beautiful golden color. Bake in the preheated oven for 25 minutes or until the tops are golden brown and flakey.

Allow the baked Peach Mango Pies to cool on the baking sheet for a few minutes before transferring them to a wire rack. Serve warm or at room temperature.