01 -
Preheat the oven to 220°C (425°F). Line two baking sheets with parchment paper.
02 -
On a lightly floured surface, unroll 1 round of pie dough and flatten it. Cut it into 3 even circles about 6 cm (2½ inches) in diameter using a cookie cutter or small knife. Repeat with the remaining pie dough.
03 -
Transfer all 9 circles of dough to the prepared baking sheets.
04 -
Cut the rhubarb slices into pieces slightly shorter than the width of the dough rounds. Place 4 or 5 pieces side by side on top of each dough circle.
05 -
Sprinkle the granulated sugar evenly over the rhubarb on each galette.
06 -
Fold the perimeter of the dough up and over the rhubarb, creating a rustic edge with the filling exposed in the center.
07 -
In a small bowl, whisk the egg with 2 tablespoons water until well combined. Lightly brush the egg wash evenly over the pie crusts.
08 -
Sprinkle turbinado sugar generously around the folded edges of each galette.
09 -
Bake until the crusts are golden brown and very crisp, 20 to 22 minutes.
10 -
Let cool at least 5 minutes before serving. Serve warm or at room temperature.