01 - In a large bowl, whisk together flour, sugar, and salt. Add cold cubed butter and cut in with a pastry blender or fork until mixture resembles coarse crumbs.
02 - Gradually add ice water, stirring just until dough begins to come together. Turn onto a lightly floured surface, knead gently, and form into a disk. Wrap in plastic and refrigerate for at least 30 minutes.
03 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
04 - In a small bowl, mix strawberry jam with diced fresh strawberries.
05 - On a floured surface, roll out dough to approximately 0.125 inches thickness. Use a heart-shaped cookie cutter measuring 3 to 4 inches to cut out 16 hearts.
06 - Place 8 hearts on the prepared baking sheet. Spoon approximately 1 tablespoon of strawberry filling onto the center of each, leaving a border.
07 - Brush edges with beaten egg mixed with water. Top with remaining hearts and press edges firmly to seal. Crimp edges with a fork.
08 - Brush tops of pies with egg wash and sprinkle with coarse sugar.
09 - Cut a small slit in the top of each pie to allow steam to escape during baking.
10 - Bake for 18 to 22 minutes until golden brown. Cool slightly before serving.