Preheat your oven to 375°F (190°C).

Roll out 2 pie crusts to fit a large baking sheet or slab pie pan, trimming the edges as needed.

Line the crust with parchment paper and fill with pie weights. Bake for 10 minutes, remove weights, then bake for another 5-7 minutes until lightly golden. Let cool completely.

Rinse and dice the strawberries and blueberries, then mix with lemon juice, cornstarch, sugar, and salt in a large bowl until well combined.

Roll out the remaining pie crust and cut into strips or shapes for a lattice design.

Brush the bottom crust with egg wash, pour in the berry mixture, dot with cubed butter, and arrange the crust design on top.

Bake for 50 minutes or until crust is golden brown and filling is bubbling. Cover edges with foil if browning too quickly.

Allow the pie to cool for at least 2 hours before slicing.