Line a shallow bowl with parchment paper. Set aside.

In a stainless steel pan, cook the butter over medium heat for 10-12 minutes, or until there are medium brown butter solids and the butter smells nutty.

Scrape the butter into the bowl and chill in the freezer until firm, about 1 hour.

Once completely frozen, remove the parchment paper and cut the butter into cubes. Place it back in the freezer until ready to use.

In a stand mixing bowl, combine the flour and salt. Then add the cubed browned butter. Mix the butter on low speed until small, pea-sized pieces remain.

Measure out the water and vinegar into a cup, then add ice. Stir to melt some of the ice and chill the water.

With the mixer running on low, drizzle the ice water into the bowl by the tablespoon.

When the dough starts to clump around the paddle, stop mixing. It should feel moist and soft, but not sticky.

Divide the dough into two rounds. Wrap each one in plastic wrap and roll them into flat round discs. Chill in the fridge for at least 1 hour.

Preheat the oven to 425 F/218 C.

Take one disc of dough from the fridge and place it on a lightly floured surface.

Roll it into a circle about ⅛ inch thick and 12 inches in diameter, then transfer to a 9-inch metal pie pan.

Roll the second disc in the same way and cut out 1 inch strips.

In a large bowl, combine the strawberries, peaches, sugar, lemon juice, lemon zest, cornstarch, and salt.

Pour the filling into the pie dish, leaving all of the excess liquid in the bowl.

To make the lattice, arrange the vertical strips on the top of the filling, following the lattice pattern.

Brush the top crust of the pie with the egg wash and sprinkle with turbinado sugar.

Place the pie on a rimmed baking sheet. Bake for 25 minutes, then decrease the heat to 350 F/180 C and continue baking for another 40-50 minutes.

Let the pie cool on a wire rack for at least 4 hours before serving.