For the turnovers:
1 package puff pastry sheets
4 large cooking apples
1/2 cup sugar
1 tablespoon cornstarch
1 teaspoon lemon juice
1/4 teaspoon ground cinnamon
For the glaze:
1/2 cup powdered sugar
1 tablespoon water
Peel, core, and dice the apples. In a medium saucepan over low heat, cook the apples, sugar, cornstarch, lemon juice, and cinnamon stirring frequently, until apples are tender. Refrigerate until cool.
Thaw the puff pastry at room temperature for 20 minutes.
Preheat oven to 400.
Unfold the first sheet of pastry on a lightly floured surface. With a rolling pin, roll it into a 12 inch square and cut into four 6-inch squares. Repeat with the second sheet.
Place 1/4 cup apple mixture in the center of each square. Brush the edges with water and fold to form triangles, sealing the edges firmly.
Place on baking sheets and bake for 25 minutes or until golden. Cool on wire rack.
To make the glaze, stir together the sugar and water. Using a spoon, drizzle over top of turnover, allowing to set before serving.