In a large bowl, toss together peaches, ¾ cup (150 grams) sugar, lemon zest and juice, and salt. Let stand for 30 minutes.

On a lightly floured surface, roll All-Butter Piecrust into a 13½-inch circle (about ⅛ inch thick). Transfer to a 9-inch pie plate (see Note), pressing into bottom and up sides. Trim dough to ½ inch beyond edge of plate. Fold edges under, and crimp as desired. Using a decorative cutter, cut shapes out of scraps, rerolling as necessary. Place on outer edge of piecrust, using a little water to adhere, if needed. Freeze for 30 minutes.

Transfer 1 cup peach mixture to a small bowl, and mash with a fork. Using a colander, strain remaining peach mixture over a large bowl. Reserve ½ cup (132 grams) peach liquid; discard remaining peach liquid, or reserve for another use. Return drained peaches to large bowl, and toss with cornstarch.

Position oven rack in bottom third of oven. Preheat oven to 400°F (200°C).

In a small skillet, whisk together reserved ½ cup (132 grams) peach liquid, pectin, reserved vanilla bean seeds, nutmeg, and remaining 2 tablespoons (24 grams) sugar. Cook over medium heat until pectin dissolves and mixture is slightly thickened, 3 to 4 minutes.

Toss together peach mixture and reserved 1 cup mashed peaches; pour into prepared crust. Drizzle with pectin mixture. Top with Browned Butter Pecan Streusel. Place pie on a foil-lined baking sheet. (Filling may look a bit shallow but will fill crust once baked.)

Bake for 20 minutes, loosely covering crust with foil to prevent excess browning, if needed. Reduce oven temperature to 375°F (190°C), and loosely cover pie with foil. Bake until crust is golden brown and filling is bubbly, 48 to 52 minutes more. Let cool completely before slicing.