Wide Lattice Peach Pie with Tarragon Butter

Directions

1. To make the crust, combine the flours, sugar, and sea salt in a large mixing bowl. Grate in the butter and gently mix it into flour with your fingertips. Gradually drizzle in ice water while folding mixture with a Silicone spatula. Add just enough water so that dough holds together. If you're new to homemade pie dough, add as much water as you need to easily work with the dough; I've found a wetter dough is preferable to overworked dough—just use plenty of flour when rolling it out.
2. Turn dough out onto a lightly floured surface and gather into a mound. Divide into 2 discs and wrap each tightly with plastic wrap. Chill dough in the fridge for at least 30 minutes or up to 5 days.
3. For the tarragon butter, melt the butter in a small saucepan over medium heat. Add 2 sprigs tarragon and turn heat to low. Steep tarragon for 20 minutes. Remove sprigs and set butter aside.
4. Position oven rack in the center of your oven and preheat to 425° F. Set a rimmed baking sheet in the oven to preheat as well.
5. Liberally butter a 9-inch pie dish. On a lightly floured surface, roll one of the discs of dough into a 14-inch circle. (Parchment paper is a great non-stick rolling surface.) Fold dough round into quarters and unfold in the prepared pie dish. Press dough into sides and bottom, and trim all but 1-inch of the overhanging dough. Set pie dish in the refrigerator to chill while you prepare the rest of the pie.
6. Prepare the filling by combining peaches, sugar, ground tapioca, lemon zest and juice, nutmeg, and sea salt. Set aside.
7. On a lightly floured surface, roll the second disc of dough into a rough 10- by 15-inch rectangle. Use a pastry cutter or sharp paring knife to cut seven 2-inch strips.
8. Working quickly, spoon the filling into chilled pie shell and drizzle with reserved tarragon butter. Lay 4 dough strips parallel across the pie. Weave in the remaining 3 in the other direction. Trim any excess dough, fold the bottom crust up around the edge, and crimp. Brush top of crust with egg white and sprinkle with remaining tablespoon sugar.
9. Set on preheated baking sheet and slide into oven. Bake pie for 15 minutes. Rotate pan, turn heat down to 350° F, and bake for another 35 to 45 minutes, or until pie is golden brown and the filling is bubbling. (If edges browns too quickly, tent with foil.)
10. For a set filling, allow pie to cool completely, 3 hours or more.