In a large mixing bowl, combine all-purpose flour, sugar, and salt, creating a dry mixture. Shred cold butter into the mixture and blend until it resembles coarse crumbs. Gradually add iced water, blending until a dough forms. Divide the dough into two disks, wrap them in plastic wrap, and refrigerate for at least 2 hours to firm up.

Score the ripe peaches on the bottom with a small X. Blanch them in boiling water for 2 minutes, then quickly transfer to an ice bath. Peel the skin off and slice the peaches into thin wedges.

In a large mixing bowl, gently combine sliced peaches and fresh blueberries. Add granulated sugar, fresh lemon juice, lemon zest, cinnamon, and corn starch, mixing until well coated.

Roll out one disk of chilled dough and place it in a pie dish. Pour peach and blueberry filling into the crust. Roll out the second disk to fit over the top; cover it or create a lattice pattern. Trim excess crust and crimp edges.

Preheat oven to 350°F (175°C). Brush the top crust with an egg wash from beaten egg and milk. Bake pie for 50-60 minutes until filling bubbles and crust is golden brown.

Let the pie cool for at least 15 minutes before serving to allow filling to set. Serve warm with a scoop of vanilla bean ice cream.