In a large bowl, whisk together the flour and salt. Add the cold butter cubes and use a pastry blender or your fingertips to cut the butter into the flour until the mixture resembles coarse crumbs. You should still see small pieces of butter.

Gradually add the ice water, one tablespoon at a time, mixing gently after each addition. Stop adding water when the dough just comes together. Be careful not to overmix.

Form the dough into a disk, wrap it tightly in plastic wrap, and refrigerate for at least 30 minutes, or up to 2 hours. This chilling time is crucial for a flaky crust.

While the dough is chilling, prepare the plum filling. In a large bowl, combine the sliced plums, granulated sugar, flour, grated ginger, and lemon juice. Toss gently to coat the plums evenly.

Preheat your oven to 375°F (190°C). On a lightly floured surface, roll out the chilled dough into a 12-inch circle. Don’t worry if it’s not perfectly round – the rustic look is part of the charm!

Transfer the dough to a baking sheet lined with parchment paper. Arrange the plum mixture in the center of the dough, leaving a 2-inch border around the edge.

Gently fold the edges of the dough over the plum filling, pleating as you go. This will create a rustic, free-form crust.

Brush the folded edges of the dough with the beaten egg. This will give the crust a beautiful golden color. Sprinkle the coarse sugar over the egg-washed crust for added sweetness and sparkle.

Bake in the preheated oven for 35-40 minutes, or until the crust is golden brown and the plum filling is bubbly and tender.

Let the Plum and Ginger Galette cool slightly on the baking sheet before slicing and serving. Enjoy warm or at room temperature.