A galette is a free-form tart that is shaped on a baking sheet - no tart pan needed. Known as crostata in Italy, these hand-formed tarts are beautifully rustic and easy to shape and can be made with either sweet or savory filling. Galettes work best when made with a flaky-style dough, which has enough strength to hold its shape and remain crisp while in contact with warm fruit juices.

Line baking sheet with parchment paper or a silicone mat.

Generously flour a work surface and place the chilled dough on the flour. Dust the top of the dough with flour. Using a rolling pin, roll dough into a circle, turning and flipping the dough as needed with a bench scraper to prevent sticking, until the circle measures 14 inches wide and 1/8 inch thick. Starting at one edge, roll the dough around the rolling pin and transfer to prepared baking sheet. Refrigerate for 30 minutes.

Preheat oven to 400°F and place a rack in the lower third.

Use a paring knife to cut and pit the plums; slice plums into ½-inch-thick wedges. Place the prepared fruit into a medium bowl and toss with granulated sugar and flour.

Mound the fruit mixture in the center of the chilled dough round, leaving a 1 ½-inch border. Fold the border up around the fruit, pleating it to make a pretty, circular enclosure and leaving the center open. Brush the top of the pleated dough with the beaten egg and sprinkle the turbinado sugar over the whole galette.

Bake galette until the crust is deep golden brown and fruit is bubbling, 40 to 45 minutes. Use a metal spatula to lift the galette slightly and and check the underside of the crust, which should be a beautiful brown color. Transfer to a rack to cool for 15 minutes.

To serve: Transfer the galette to a serving plate. Slice and serve warm accompanied by vanilla ice cream.