For the Pastry:
On a lightly-floured work surface, roll out pastry sheets to 1/8-inch thick. Cut each sheet into 4 equal squares. Spoon 1 heaping tablespoon jam in center of each piece, brush edges with egg yolk, fold into triangles, and press tightly to seal. Transfer pies to a parchment-lined, rimmed baking sheet and freeze until firm, about 30 minutes.
Preheat oven to 375°. Bake pies until golden and puffed, about 20–25 minutes. Let cool slightly on baking sheet set on a wire rack. Whisk together lemon juice and confectioners’ sugar until smooth. Drizzle glaze over cooled pies. Can be served warm or at room temperature. Store in an airtight container at room temperature for up to three days.
For the Jam:
In a large bowl, crush strawberries to release juices (a potato masher works well). Transfer to a large saucepan and stir in honey and lemon juice. Bring to a simmer over medium-high heat, stirring frequently, until jam is thickened and bubbles completely cover surface, about 10 minutes. Transfer jam to a large bowl and let cool to room temperature. Store cooled jam in a sealed jar in the refrigerator for up to 10 days.
Makes 1 and 1/2 cups