Line a shallow bowl with parchment paper and set aside.

In a stainless steel pan over medium heat, cook butter for 10-12 minutes until medium brown solids form and butter smells nutty. Scrape into lined bowl and freeze for 1 hour until firm.

Remove parchment, cut butter into cubes, and keep frozen until ready to use.

In a stand mixer bowl, combine flour and sea salt. Add browned butter cubes and mix on low until mixture resembles coarse sand (about 3 minutes).

Prepare ice water by mixing water, apple cider vinegar, and ice cubes. Drizzle ice water into flour mixture slowly while mixing on low until dough clumps but is not sticky.

Divide dough into two 335-gram discs, wrap in plastic wrap, and chill for at least 1 hour.

Preheat oven to 425°F (218°C). Roll out one dough disc on a floured surface to 12 inches diameter and ⅛ inch thick. Transfer gently to a 9-inch pie pan and chill.

Roll out second disc the same way and cut into 1-inch strips. Chill strips on parchment-lined tray.

In a large bowl, mix peaches, strawberries, sugar, lemon juice, lemon zest, cornstarch, and salt. Pour filling into crust, discarding excess liquid.

Arrange vertical strips over filling. Weave lattice by folding every other strip, adding horizontal strips, then unfolding. Trim excess dough, tuck edges, and crimp.

Brush lattice with whisked egg and sprinkle with Turbinado sugar.

Place pie on rimmed baking sheet. Bake at 425°F for 25 minutes. Reduce heat to 350°F (180°C) without opening oven, bake 40-50 minutes more. Cover crust with foil if browning too fast.

Cool on wire rack for at least 4 hours before serving.