For the crust:
5 cups (640 grams) all-purpose flour, plus more for dusting
2 tablespoons granulated sugar
1 1/2 teaspoons fine salt
2 cups (450 grams) cold, unsalted butter, cut into tablespoon-sized pieces
6 to 9 ounces (175 to 265 milliliters) cold, well-shaken buttermilk

For the filling:
3 1/2 pounds (1575 grams) strawberries
3/4 cup (150 grams) granulated sugar
6 tablespoons (50 grams) cornstarch
1 teaspoon finely grated lemon zest
Pinch salt
1 tablespoon fresh lemon juice
1 large egg
Turbinado sugar, for sprinkling

Make the crust: Whisk the flour, sugar, and salt together in a large bowl.

Working quickly, add the butter to the flour and toss to coat. Using your fingertips or the palms of your hands, press each piece of butter into a flat sheet. Keep tossing the butter in the flour as you go to ensure that each butter piece is coated with flour. The idea is to create flat, thin shards of butter that range from about the size of a dime to about the size of a quarter. If at any time the butter seems warm or soft, briefly refrigerate the whole bowl.

Sprinkle about 1/2 cup of the buttermilk over the flour mixture. Use a gentle hand or wooden spoon to stir the buttermilk into the flour until just combined. If the dough seems dry, add more buttermilk a couple teaspoons at a time. You have added enough buttermilk when you can pick up a handful of the dough and easily squeeze it together without it falling apart.

Gently press the dough together into one piece. Cut the dough into 2 pieces, making one slightly larger than the other. The larger piece will be the base of the pie, the smaller piece will be the top.

Wrap each piece of dough separately in plastic wrap and press it into a rectangle. Refrigerate at least 2 hours and up to overnight.

Lightly flour a work surface. Roll the larger piece of dough into a rectangle measuring roughly 12 by 17 inches. Transfer it to a 10x15-inch jellyroll pan and gently press the dough into the pan; trim the edges evenly. If necessary, repair any cracks or tears in the dough, then fold the edges under and crimp them into a decorative pattern. Refrigerate while you prepare the other crust and the filling.

Line a baking sheet with parchment paper. Roll out the second piece of dough 1/8- to 1/4-inch thick and use a round cookie or biscuit cutter (or multiple-sized cutters) to cut the dough into rounds. Transfer the rounds to the lined baking sheet and refrigerate. Gather the dough scraps and cut one more round of circles. Add these rounds to the baking sheet and discard the remaining dough scraps.

Arrange a rack in the lower third of the oven and heat to 425°F.

Make