In a saucepan on medium-low heat add the strawberries, water, sugar, and cornstarch and mix. Cooke for 3-4 minutes and using a potato masher or fork smash the strawberries a bit. Remove from the stovetop and let cool for 10-15 minutes.
Preheat oven to 400 degrees
Sprinkle some flour on a cutting board and lay out the puff pastry. Using a rolling pin or cup roll out the creases in the puff pastry. Cut the puff pastry into four large squares.
Add about 2 tablespoons of the strawberry filling into the middle of the squares.
Fold the corner over to form a triangle. Using a fork crimp the edges to seal.
Transfer the turnovers to a baking sheet and brush the top with the egg whites. Using a small knife make to small slit in the top.
Bake 15-18 minutes.
For the Glaze
In a small bowl add the powdered sugar and 1 tablespoon of milk. Mix and add the rest of the milk if needed for desired consistency.
Let turnovers cool for 5 minutes then using s spoon drizzle over the top.
Video
Notes
You can use frozen strawberries if desired, thaw first, and don't add any water.You can adjust the sugar according to how sweet or tart your strawberries are.If you don't want a glaze on top, you could sprinkle granulated sugar on top before baking. Or give them a dusting of powdered sugar just before serving.Make sure you pinch the edges to prevent the filling from oozing out.Store these easy strawberry turnovers in an airtight container in the refrigerator for up to 4 days.