In a medium saucepan, combine the diced strawberries, granulated sugar, cornstarch, water, and a pinch of salt. Heat the mixture over medium heat, stirring occasionally, until it becomes bubbly and slightly thickened. This should take about 3-4 minutes.

Remove from heat and stir in the lemon juice. Set aside to cool to room temperature.

Unroll your thawed puff pastry on a lightly floured surface. Using a rolling pin, gently smooth the dough to form a square or rectangle.

Cut the dough into 4 equal-sized squares (you’ll have 8 squares total if using both sheets of puff pastry).

Place 1-2 tablespoons of the strawberry filling in the center of each pastry square.

In a small bowl, whisk together the egg and water to create the egg wash.

Brush the edges of each pastry square with the egg wash. Then, fold the pastry corners together to form a triangle shape. Press the edges with a fork or your fingers to seal them tightly.

Transfer the turnovers to a parchment-lined baking sheet. Brush each turnover with the remaining egg wash.

Bake in a preheated 400°F (200°C) oven for 15-20 minutes, or until golden brown and puffed.

Allow the turnovers to cool for at least 10 minutes before serving.

While the turnovers are cooling, whisk together the confectioner's sugar, milk, and vanilla extract in a small bowl until smooth. Adjust the consistency by adding more sugar for thickness or more milk for a thinner glaze.

Drizzle the vanilla glaze over the cooled turnovers. Serve with any remaining strawberry filling on the side for dipping. Enjoy!