prepared pastry dough, enough to yield 2 9-inch rounds
1 teaspoon lemon zest
1 large egg, beaten
coarse (turbinado) sugar
Place racks in the upper third and center of the oven, then preheat oven to 400° F. Line two baking sheets with parchment paper or silicone mats.
Place first pie crust on a well-floured surface and roll into a 1/8 inch thickness. With a 3-inch heart shaped cookie cutter, cut 12-14 hearts from the rolled crust. Transfer the hearts to a plate or baking sheet and place in the refrigerator. Roll and cut the second crust. After cutting both crusts, you should have 24-28 hearts total.
Beat the egg in a small bowl to create an egg wash, then lightly brush over half (12-14) of the hearts. Place 1 heaping teaspoon of the strawberry fruit filling in the center of each egg washed heart, ensuring that you place a piece of fruit in each one.
Gently stretch each of the remaining hearts with your fingers to make them slightly larger, then set them on top of the filling-topped hearts. With your fingers, gently press the edges together. With the tines of a fork, press around the edges of the hearts to seal, then use a small knife to cut two small vents in the top of each heart. Brush the tops of each complete heart with the beaten egg, then sprinkle with turbinado sugar.
Place the hearts 1 inch apart on the prepared baking sheets. Bake for 12 minutes, until golden and bubbling, rotating the pans' position half way through. Remove from oven and allow to cool on pans for 10 minutes, then transfer to wire rack to cool completely