1. Make the Pie Crust:

• Freeze Butter: Place the cubed butter in the freezer for about 1 hour before starting.
• Combine Dry Ingredients: In a food processor, combine the flour, salt, and 3 tablespoons of granulated sugar. Pulse about 5 times until mixed. (Alternatively, whisk together in a large bowl).
• Cut in Butter: Add the very cold butter cubes to the food processor. Pulse about 12 times, or until the mixture resembles coarse meal with some pea-sized pieces of butter remaining. (Alternatively, use a pastry blender or your fingertips to cut the butter into the flour mixture in the bowl).
• Add Ice Water: Remove ice from your water. Add 2 tablespoons of ice water to the food processor (or bowl). Pulse 2-3 times (or mix briefly with a fork). Add more ice water, 1 tablespoon at a time, pulsing (or mixing) just until the dough just barely starts to clump together. It should still look crumbly but hold together when pinched. Do not add too much water or the crust won’t be flaky (usually 2-4 tablespoons total).
• Form and Chill Dough: Turn the crumbly dough out onto a lightly floured surface. Gently gather it into a rough disc, handling it as little as possible. Wrap the dough disc tightly in plastic wrap and refrigerate for at least 1 hour (or up to 2 days). (Dough can be frozen for up to 1 month; thaw overnight in the refrigerator).  
   

2. Prepare the Strawberry Chocolate Filling:

• Macerate Strawberries: In a medium bowl, combine the halved strawberries, 3 tablespoons granulated sugar, and vanilla extract. Stir gently. Let sit at room temperature for about 30 minutes, or until the sugar dissolves and the strawberries soften slightly and release some juices.
• Drain and Finish Filling: Drain the strawberries very well, discarding the excess syrup (or save it for another use). Sprinkle the cornstarch over the drained strawberries and stir gently to coat. Fold in the milk chocolate chips. Place the filling mixture in the refrigerator until ready to use.

3. Assemble and Bake the Galette:

• Preheat Oven: Preheat the oven to 350°F (175°C). Place a large baking sheet on your counter.
• Roll Out Dough: Remove the chilled pie dough from the refrigerator. On a large sheet of lightly floured parchment paper, roll the dough out into a circle roughly 12-14 inches in diameter and about 1/8 inch thick. Rotate the dough occasionally and lightly flour underneath as needed to prevent sticking. Don’t worry about a perfect circle.
• Chill Rolled Dough (Optional but Recommended): Carefully slide the parchment paper with the dough circle onto the baking sheet and place it in the refrigerator for about 15 minutes to firm up slightly (this makes assembly easier).
• Add Filling: Remove the dough from the refrigerator. Spoon the chilled strawberry/chocolate mixture into the center of the dough circle, leaving a 2-inch border all around. Gently pat the filling down slightly.
• Fold Crust: Carefully fold the 2-inch border of dough up and over the edges of the filling, pleating the dough as you go around the circle. The center of the galette should remain open, exposing the filling.
• Egg Wash and Sugar: Brush the folded edges of the galette crust with the beaten egg. Sprinkle the egg-washed crust generously with granulated sugar.
• Bake: Place the baking sheet with the galette into the preheated oven. Bake for 25-30 minutes, or until the crust is golden brown and the filling is bubbly.
• Cool and Serve: Remove the galette from the oven and let it cool on the baking sheet for at least 5-10 minutes before slicing. Serve warm, optionally with a scoop of vanilla ice cream.