Combine blueberries, raspberries, sugar, lemon juice, lemon zest, flour and sugar in a large bowl. Set aside.

Defrost pie shells according to package instructions.

Once defrosted transfer 1 pie shell to glass pie pan that has been lightly dusted with flour. Work defrosted pie shell to fit in the pie pan.

Pour filling into the pie pan, pile higher in the middle. Place in the refrigerator, until top crust is prepared.

Place the second pie shell upside down on a piece of parchment paper. Flatten and roll out pie shell. You are trying to flatten the shell and can repair any cracks by pressing dough together.

Once rolled out use cookie cutter to create vents in pie shell...you could use a knife to cut vents.

Remove pie pan from fridge, place flattened pie crust on top of filling. Seal the edges by pressing the edges of the crusts together.

Create an egg wash, combine egg and water, brush egg wash on top of pie.

Dust pie crust with ¼ teaspoon granulated sugar.

Bake pie in 425 oven for 20 minutes. Then turn the temperature down to 350 and continue baking for 35-40 minutes. Bake until top is golden brown and middle of pie filling is bubbling.

Remove from oven and let sit for at least 20 minutes.