Add the flour, sugar and salt to a food processor and pulse just until combined. In a small bowl, whisk together the egg, vinegar and water. Add the cold butter pieces into the food processor and pulse until small coarse crumbs remain. Sprinkle the water/egg mixture over the flour and pulse again until the dough comes together.: The moment you pulse the mixture you should notice a faint, dry scent of flour and a uniform texture in the bowl, which signals that the base is ready for the butter; using short pulses prevents overworking the gluten, which keeps the crust tender. If the mixture looks uneven or has lumps, pulse a few more quick times but avoid creating a powdery flour cloud. A common mistake is blending too long so the mixture heats up and the butter begins to soften, which will ruin flakiness.
Remove the dough with your hands and wrap it in plastic wrap. This dough makes enough for 2 galette crusts, so separate it into 2 sections now, or separate it after it's refrigerated. Refrigerate the dough for 30 minutes. Freeze one of the other balls of dough!: As you whisk, you'll see the egg lighten and the tiny ripples of liquid reflect light, indicating the wash is smooth; the vinegar will be invisible but its effect on tenderness is real. Chill this mixture if your kitchen is warm, because a cool wash helps keep the dough cold. A typical slip-up is using warm water which can make the dough sticky and difficult to handle.
After 30 minutes, preheat the oven to 400 degrees F.: When the butter is properly cut in, the texture resembles coarse crumbs with pea sized pieces of butter visible, which is what creates flaky layers during baking. You should still see tiny flecks of white butter among the crumbs. If everything looks uniformly pasty, you pulsed too much; at that point chill the mixture and proceed cautiously.
Place the cherries in a bowl. Toss with the sugar, cornstarch and salt, making sure to coat all the cherries. Drizzle in the vanilla extract and toss.: Watch for the dough to clump and hold together when pressed, a tactile cue that it is ready; it should not be sticky or wet, but cohesive and slightly tacky. If it seems dry, add a teaspoon of ice cold water at a time. Overmixing here will develop gluten and yield a tougher crust, so pulse sparingly and stop the moment pieces cling.
Remove one of the crusts from the fridge. (The other is good for another week or so, or it can be frozen.) Roll one of the pie crusts into a rustic shape – no shape necessary really – until it is about 1/4 inch thick. Place the dough on a parchment-lined baking sheet. Place the cherries in the center leaving a 2-inch+ border of crust. Top with the butter cubes.: As you shape the dough into a disk by hand, you will feel the temperature change, and that warmth signals you should work quickly to avoid melting the butter . Wrap tightly to prevent drying out and label so you know it's one of two crusts; a common oversight is leaving it uncovered, which causes a dry skin on the dough that will crack when rolled.
Once the cherries are placed, fold the crust over top of them. Brush the crust with the beaten egg wash. Sprinkle it with the raw sugar. Bake the galette until the crust is golden, about 40 to 45 minutes.: Dividing the dough ensures even chilling and easier rolling later; each piece should feel dense and slightly cool. If you plan to freeze one, flatten it into a disk first so it thaws evenly. A mistake people make is freezing a very thick lump, which takes too long to thaw and increases the chance the butter will soften unevenly.
Remove it and let cool slightly, then slice. Serve warm with vanilla ice cream.: Chilling firms up the butter , making it easier to roll and resulting in flakier layers when baked; you will notice the dough becoming less tacky and easier to handle. Do not skip this rest, since rolling warm dough often tears and sticks. A shortcut some take is briefly freezing, but that can make the dough brittle and prone to cracking while rolling.
Freeze one of the other balls of dough: Freezing preserves a second crust for future use and will keep its texture intact if wrapped well; flash freeze on a tray before bagging to avoid the pieces sticking together. Make sure to write the date, because frozen dough is best used within a month. People sometimes forget to wrap tightly, which leads to freezer burn and dried out dough.
After 30 minutes, preheat the oven to 400 degrees F: Preheating sets the stage so the crust begins to brown and the butter creates steam pockets right away; the oven should feel fully hot when you slide the galette in, which helps achieve that crisp, golden finish. An oven that is not fully heated will lengthen bake time and may yield a soggy bottom. Always use an oven thermometer if your oven's accuracy is uncertain.
Place the cherries in a bowl: Handling the cherries now you will see their vibrant color and feel their plumpness; a light squeeze should release juice if they are ripe. This tactile check helps you judge sugar needs; underripe fruit may need a touch more sweetness. A common misstep is adding too much sugar and overpowering the cherries' natural brightness.
Toss with the sugar, cornstarch and salt, making sure to coat all the cherries: As you toss, the sugar will begin to draw out juices and the cornstarch will cloak the fruit, its powdery sheen disappearing into glossy fruit juice. Proper coating ensures the filling thickens evenly during baking. If some berries are missed, pockets of runny juice can form, so be thorough but gentle to avoid breaking fruit prematurely.
Drizzle in the vanilla extract and toss: The aroma of vanilla extract will lift the fruit, adding warmth and depth; a light hand is all you need to complement the tartness. Stir until the vanilla is evenly distributed and the cherries glisten. Overdoing flavorings can mask the primary star, which here is the cherry, so less is more.
Remove one of the crusts from the fridge: The chilled dough should feel firm but pliable; let it sit for a minute if it is rock hard so it is easier to roll. If it is too cold, it can crack while rolling, and if too warm, it will stick, so timing is key. A common misstep is forcing a cold disk, which results in uneven thickness.
Roll one of the pie crusts into a rustic shape until it is about 1/4 inch thick: As you roll, the dough should unfurl smoothly, and you will see small flecks of butter in the sheet; stop when the thickness is even and you can still lift it without tearing. The rough edges are part of the charm. Rolling too thin risks a soggy base, so aim for that quarter inch thickness for a sturdy, flaky crust.
Place the dough on a parchment lined baking sheet: The parchment prevents sticking and makes it easy to transfer the galette into and out of the oven, plus it helps promote even browning underneath. Centering the dough on the sheet gives you room to fold. Skipping parchment often leads to clean up headaches and possible sticking.
Place the cherries in the center leaving a 2 inch plus border of crust: Piling the filling centrally avoids seepage and keeps the edges free for folding, and you will notice the fruit mounding slightly, signaling a generous filling. Leaving a proper border prevents overflow and ensures a neat fold. A too thin border will cause filling to spill and burn on the sheet.
Top with the butter cubes: Dotting pieces of butter across the cherries creates pockets of richness that melt into the fruit, producing glossy flavor bursts. The butter will sizzle and meld with fruit juices during baking. Do not substitute with melted butter at this point because it will make the filling greasy and overly runny.
Once the cherries are placed, fold the crust over top of them: Folding creates the characteristic rustic rim and traps the filling slightly so it does not wander; the edges should overlap intermittently for a pleasing, uneven border. Press lightly where folds meet to secure them. Over folding or pressing too firmly can compress the fruit and cause an uneven bake.
Brush the crust with the beaten egg wash: The egg wash will immediately give the crust a sheen and encourage deep golden color, and a light, even coat prevents pooling which can burn. Use a pastry brush and gentle strokes for an even finish. A common mistake is applying too much, which can create a sticky, browned patch rather than a delicate gloss.
Sprinkle it with the raw sugar: The raw sugar will catch the oven light and become slightly crunchy, creating an attractive contrast to the soft filling; it also enhances sweetness on the first bite. Use just enough to sparkle without turning gritty. Over-sugaring can leave an unpleasantly crunchy surface.
Bake the galette until the crust is golden, about 40 to 45 minutes: During baking the kitchen will fill with the scent of warm fruit and butter, and you will see the juices bubble at the center while the crust turns a rich golden brown, all cues that it is nearly done. Rotating the sheet midway ensures even browning. Removing it too soon results in a runny filling, while overbaking dries the crust and dulls the cherry flavor.
Remove it and let cool slightly, then slice: Letting the galette rest helps the filling set so slices hold together, and you will notice the bubbling quiet as the juices thicken, an important sign that it is time to cut. A short rest also prevents burns when serving warm. Cutting immediately often causes the filling to spill and loose presentation.
Serve warm with vanilla ice cream: The contrast of warm, jammy cherries and cold vanilla ice cream creates a perfect balance of temperature and texture, with the ice cream slowly melting into the fruit for an indulgent finish. Garnish if desired, but the simple pairing is usually best. Serving it stone cold masks the aroma and reduces the sensory impact.