Preheat your oven to 375°F (190°C). Roll the pie dough into a 12-inch circle, carefully pressing it into a 9-inch pie plate. To prevent bubbles, cover the crust with parchment paper and weigh it down with pie weights or dried beans. Bake for 15 minutes until lightly golden.

In a mixing bowl, combine fresh lemon juice and tapioca. Gently fold in sliced peaches and granulated sugar, mixing until all the fruit is well coated.

Once your pie crust is pre-baked, remove it from the oven and let it cool slightly. Pour the peach mixture into the crust, spreading the slices evenly.

In a separate bowl, cut cold unsalted butter into brown sugar until crumbly. Add flour, nutmeg, and vanilla extract, mixing by hand until the crumble resembles coarse sand.

Sprinkle the crumble evenly over the peach filling. Bake the pie at 400°F (204°C) for 20 minutes, then reduce the temperature to 375°F (190°C) and continue baking for an additional 25-30 minutes.

Remove the pie from the oven and let it cool on a wire rack for 3 to 4 hours before serving.