Begin by preheating your oven to 400 degrees F. Line a baking sheet with a silicone mat or parchment paper and set aside.
Next, in a medium bowl, combine strawberries, sugar, cornstarch, and vanilla and set aside.
Working with half of your prepared pie dough at a time, on a lightly floured surface, roll out the dough until it is about 1/8 inch thick. Using a 6-inch cookie cutter (or round bowl or plate with a 6-inch diameter), begin cutting out your rounds. Repeat with the remaining half of the dough. Form any excess dough back into a ball, roll out and cut again. Repeat this until you've used as much dough as possible.
With all of the rounds cut, in a small bowl, whisk together the egg and water. Lightly brush this around the edges of each pie dough round. Then, place about 2 - 3 tablespoons of the strawberry filling onto one-half of each round. Fold the opposite side of the dough round over to enclose forming a half circle. Using a fork, gently press the edges together to seal; then pierce the top of each pie to allow any steam to escape. Brush the tops of each hand pie with the egg wash and then generously sprinkle each with sanding sugar.
Bake for about 20 to 25 minutes until the pies are golden brown. Transfer the pies to a wire rack to cool slightly before serving.
You can get my Go-To Homemade Pie Crust recipe HERE.