Prepare the Brown Butter Pie Crust:

• In a medium saucepan, melt the butter over medium heat. Allow it to cook until it turns a golden brown color and develops a nutty aroma, about 5-7 minutes. Remove from heat and set aside to cool slightly.

• In a large bowl, combine the flour and salt. Pour the brown butter into the flour mixture, mixing until the dough starts to come together.

• Add the cold water, vinegar, and egg, mixing until the dough just begins to form. If needed, add a bit more water, 1 tablespoon at a time, until it holds together.

• Turn the dough onto a lightly floured surface and knead it a few times to bring it together. Divide the dough into two equal portions, wrap them in plastic wrap, and refrigerate for at least 30 minutes.

Prepare the Strawberry and Peach Filling:

• In a large bowl, combine the sliced peaches, quartered strawberries, granulated sugar, cornstarch, lemon juice, lemon zest, and salt. Toss gently to combine and set aside.

Assemble the Pie:

• Preheat your oven to 375°F (190°C). Roll out one portion of the dough on a floured surface to fit a 9-inch pie pan. Press it into the pan and trim the excess dough around the edges.

• Add the strawberry and peach filling into the prepared pie crust, spreading it evenly.

• Roll out the second portion of dough and cover the pie with the top crust. Trim any excess dough and crimp the edges to seal the pie.

• Brush the top of the pie with the whisked egg and sprinkle with Turbinado sugar, if using.

Bake the Pie:

• Bake the pie in the preheated oven for 45-50 minutes, or until the crust is golden and the filling is bubbly. You can cover the edges of the crust with foil to prevent over-browning if needed.

• Let the pie cool for at least 2 hours before serving to allow the filling to set.