These easy apple turnovers start with buttery puff pastry and a simple stovetop apple filling. Flaky, golden, and lightly glazed, they’re every bit as good as the bakery version but far easier to make at home.
In a medium skillet, melt the butter over medium heat. Add the apples, granulated sugar, brown sugar, cinnamon, nutmeg, and lemon juice. Cook, stirring occasionally, until apples are just tender, 5–7 minutes.
Mix together the cornstarch and water to make a slurry. Stir into the apple mixture, and cook 1 minute more until thickened.
Remove from the heat and cool completely.
On a lightly floured surface, unfold the puff pastry sheets. Roll lightly to smooth the creases. Cut each sheet into 4 equal squares (8 total).
Place about 2 tablespoons of the cooled filling in the center of each square. Fold into triangles and press the edges to seal well; crimp with a fork.
Place on a parchment- or silicone-lined baking sheet. Chill 15 minutes.
Preheat oven to 400°F (200°C).
Whisk together the egg and water to make an egg wash. Brush the turnovers with the egg wash (you won’t use it all) and sprinkle with coarse sugar if desired.
Bake for 18–22 minutes, until puffed and golden.
To make the glaze:
In a small bowl, whisk together the confectioners' sugar, 1 tablespoon milk (or cream), and vanilla. Add more milk (or cream) a small amount at a time as needed to reach the desired consistency.
Drizzle or brush the glaze over slightly cooled turnovers. Serve warm or at room temperature.