Make the basic galette/pie dough:
Whisk together flour and salt in a large mixing bowl. Add cubed butter and toss with your hands to cut. Squish the butter cubes in your fingers into pieces roughly the size of walnut halves.
Add water a few tablespoons at a time and mix with your hands so that the dough comes together. Form ball into a 1-2"H disk.
Wrap the disk in plastic and chill for a minimum of an hour, or preferably overnight.
Make the peach and ginger galette:
Preheat oven to 425°F.
Slice peaches to roughly ¼” thickness, or as desired. In a large bowl, mix sugars, cornstarch, lemon zest, lemon juice, salt vanilla extract, and spices. Add peaches and toss until evenly coated. Set aside coated peaches.
Dust flour on a cool, dry surface for rolling out dough. Retrieve basic galette dough from refrigerator after sufficiently chilled. Using a rolling pin, press and roll the dough disc from the middle to both ends eventually shaping it into rough circle (approximately 12” in diameter). Transfer to a large parchment lined baking sheet.
Arrange peach slices in a decorative pattern of concentric circles starting in the middle and working outward. Leave roughly 2” of dough border at the edge.
Fold over pastry dough edges towards the center of the galette while leaving most of the filling showing. Brush these edges with melted butter and sprinkle with turbinado sugar.
Bake for 30-40 minutes, or until golden brown. Timing will depend on thickness of the galette.
Serve warm, but not hot. Top with vanilla ice cream or whipped cream.
*keeping skin on peaches makes for an attractive contrast, but some find the skin distracting and enjoy the more traditional pie-like skinless peaches.
For the basic galette/pie dough:
It is important that all ingredients remain cold. If your fingers warm and melt the butter at any time, place the whole mix in the freezer for 10 minutes to re-chill. Some cooks like to chill the rolled out crust once on a baking sheet or even the fully prepared galette prior to baking.
This will make your dough very sticky when it’s time to roll it out. Ideally your dough ball won’t be as uniformly moistened as something like cookie dough batter. Instead the dough ball might feel like it could come apart as you’re wrapping it in cellophane.
You can double wrap your dough ball and freeze for a few days. You can put it in a freezer bag or aluminum foil for extra protection.