Preheat your oven to 400F. Place the chilled dough onto a lightly floured surface and roll out into a thin circle, around maybe 11″ or so. It doesn’t need to be perfectly round. A galette is meant to look rustic. Place the dough onto a parchment-lined baking sheet using your rolling pin to help move it. Sprinkle the almond flour over the pastry dough evenly. The almond flour helps absorb excess juices as well as add some flavor.
Arrange the peaches over the almond flour in an overlapping layer or in a messy but level pile. Both options work, but one looks more intentional. Just make sure you don’t bring them to the edge. Leave a 2″ border around the edges so you can fold those over. Avoid piling the fruit too high in the center. Too much filling can release enough juice to make the bottom crust soggy.
Gently fold the pastry over the peaches, working around the galette.
Brush the pastry edges with egg wash and sprinkle lightly with coarse sugar (optional, but adds nice texture and shine).