Line two baking sheets with parchment paper.

Divide the pie dough into 8 equal-size pieces. If your dough has been chilled overnight, it will need to sit at room temperature a bit before rolling—this will take 10 to 15 minutes. Lightly flour your work surface and roll out each piece to a 7-inch round (or something close to round) just shy of ¼-inch thickness. Transfer the dough rounds to the prepared baking sheets, placing 4 on each sheet.

In a large bowl, combine the strawberries, vanilla sugar, cornstarch, lemon zest, and salt. Place a heaping ⅓ cup of the berry mixture on each dough round, leaving a 1 ½-inch border. Fold the edges of the dough up over the filling in loose pleats, leaving the fruit exposed in the center of each galette. Gently arrange the galettes on the baking sheets so they’re several inches from one another.

Refrigerate or freeze the galettes until the dough is firm, about 20 minutes in the fridge or 10 minutes in the freezer.

Position two racks in the center zone of your oven and preheat the oven to 400°F.

Pour 1 tablespoon of cream in the opening of each galette. Brush the edges of the dough with the egg and sprinkle each galette with sanding sugar.

Reduce the heat to 375°F. Bake until the crusts are golden brown, about 30 minutes. Rotate the pans top to bottom and front to back and continue to bake until the juices bubble from the center of each galette, about 15 minutes more. Transfer to a wire rack and let the galettes cool completely before serving. Store at room temperature in a sealed container for 1 day or up to 1 week in the fridge.