Add 6 cups of blueberries to a large bowl. Add sugar, cinnamon, and flour to the berries. Gently toss the berries until all of the berries are coated with the flour and sugar mixture. Then, set aside.
Preheat the oven to 400F. Prepare your pie crusts. Roll out on a floured surface. Place one crust on the bottom of a buttered pie plate. Make a fluted edge on the crust with your fingers. I made two of my favorite Einkorn pie crusts. I'll have to write a post soon with this delicious buttery and flakey crust. One crust is for the bottom, and the other will be made into a lattice shape for the top.
Pour the berries into the crust. The berries will heap in the center slightly. Sprinkle any extra flour, sugar, and cinnamon from the berry bowl evenly over top of the blueberries in the pie plate.
Create the top crust by rolling out the pie crust on a floured surface. Use a sharp knife or pizza cutter to make 8, 1 inch strips in the crust. Place four strips evenly across the pie going in the same direction. Then, gently pull back the two of the four strips on crust 3/4 of the way and add a pie crust strip near the edge of the pie on top of the two pie strips the are not folded back. Then, fold the pie crust strips that were folded back, back over the new strip. Repeat this step with three more strips of pie crust, alternating the two strips that the new strip lays on top of. You are creating a weaving pattern. When the weaving pattern is finished. Trim the edges with a knife and push the top edge of the crust into the bottom edge of the crust into the fluted shape with your fingers.
In a small bowl, place an egg white and a tablespoon of water and mix together. Brush over the top of the pie crust. Then, sprinkle the top of the crust with sugar. Both of these will give the top of the crust a lovely brown color without being overcooked.
Place the pie in the oven and bake at 400F for 25 minutes. Then, reduce the oven heat to 375F, gently cover the pie with foil, and bake for another 50 to 55 minutes. Bake until the berry mixture is bubbling. Remember, if you're using all frozen berries, you may need to extend the baking time by a few minutes.
Your pie is now ready! Allow the pie to cool for at least 30 minutes. If the pie is sliced into when it's too warm, all of the berries will run out instead of holding their shape in the pie slice. Store the pie in the fridge. Enjoy!