Preheat the oven to 425°F. Line a large baking sheet with parchment paper.

In a large bowl, toss together the cranberries, sugar, and orange zest until combined. Set the bowl aside.

Roll out the puff pastry sheet onto the parchment-lined baking sheet. Carefully roll it out with a small rolling pin. Use a pizza cutter to round off the corners, if desired.

Spoon the cranberry filling into the center of the puff pastry, then carefully fold the edges around the filling making a round tart. The galette doesn’t need to look perfect.

Crack the large egg into a small bowl, and beat until it is light yellow. Brush the egg wash over the edges of the galette, and sprinkle the turbinado sugar over it.

Bake the galette for 15-20 minutes, or until the cranberries are bubbling and the puffy pastry is golden brown around the edges.

If any bubbles form in the puff pastry, use a knife to pop them and they’ll deflate. Serve warm or at room temperature with powdered sugar or vanilla ice cream.