Make the shortcakes: Line a rimmed baking sheet with parchment paper. Pulse the flour, freeze-dried strawberries, granulated sugar, baking powder and salt in a food processor until the strawberries are crushed. Add the butter and pulse until it is in pea-size pieces. Whisk the heavy cream and egg in a small bowl. Pulsing constantly, drizzle the cream mixture into the flour mixture; pulse until the dough comes together. Transfer to a medium bowl and knead 3 or 4 times.
Scoop 6 balls of dough (about 1/2 cup each) onto the prepared baking sheet using a large ice cream scoop or a measuring cup, spacing the dough 2 to 3 inches apart. Refrigerate until firm, about 30 minutes.
Preheat the oven to 400 degrees F. Lightly brush each ball of dough with heavy cream and sprinkle with granulated sugar. Bake until golden and a toothpick inserted into the centers comes out clean, 20 to 25 minutes. Let cool 10 minutes on the baking sheet, then transfer to a rack to cool completely.
Meanwhile, make the filling: Puree 2 cups strawberries in a blender until smooth. (You should have about 1 cup puree.) Toss the remaining 4 cups strawberries with 1/2 cup of the strawberry puree, the granulated sugar and lemon juice; cover and refrigerate until ready to use.
Crush or finely chop the freeze-dried strawberries until powdery; transfer to a large bowl and add the heavy cream and confectioners? sugar. Beat with a mixer on medium-high speed until stiff peaks form. Add the vanilla and beat until combined. Gently fold in the remaining 1/2 cup strawberry puree. Refrigerate until ready to use.
Split each shortcake and fill with the strawberries and whipped cream.