5-6 cups blackberries, rinsed, picked clean, patted dry (if you use frozen berries, defrost and drain them)
1/2 cup to 3/4 cup sugar (depending on how sweet your berries are)
1 teaspoon lemon juice (use 2 teaspoons if using store-bought berries)
1 teaspoon lemon zest
1/2 teaspoon ground cinnamon
1/4 teaspoon almond extract
4 to 6 Tbsp cornstarch, flour, or ground quick cooking instant tapioca (use 4 Tbsp if making the pie with wild-picked berries that include a few not fully ripe berries, 6 Tbsp if making the pie with store-bought very ripe berries)
Toss blackberries with sugar, lemon, cinnamon, almond extract, quick tapioca: Place blackberries, sugar, lemon zest, lemon juice, cinnamon, almond extract, and cornstarch/flour/or ground instant tapioca in a large bowl. Gently fold the berries until they are all well coated with sugar. Let sit for 30 minutes.
Roll out bottom crust: Preheat oven to 400°F. You should have two balls of pie dough, one for the bottom crust, one for the top crust.
Roll out one of the balls of pie dough on a lightly floured surface to 12-inch diameter if you are using a 9-inch pie pan, or 13-inch diameter if you are using a 10-inch pan.
Line the bottom of your pie pan with the dough. Chill in refrigerator while you roll out the top crust.
Roll out top crust: Roll out the second ball of pie dough for the top crust. If you would like to do a lattice top, weave the dough strips as described in How to Make a Lattice Top for a Pie Crust.
Spoon berry mixture into pie crust, top with second crust: Spoon the berry mixture into the dough-lined pie dish. For a lattice top, weave strips of pie dough over the top of the fruit-filled pie dish.
For a solid top, place the second rolled-out pie dough crust on top of the pie. Press ends of strips into the rim of the bottom crust. Use scissors to trim the edges to 1/2-inch from the outer edge of the pie pan.
Fold the edges back over themselves and use your fingers to crimp to seal the edges. If you are using a solid top crust, score the top several times with a sharp knife to create air vents for the steam to escape.
Bake: Place the pie on the middle rack of the oven. Put a baking sheet on the lower rack to catch any juices that might bubble out of the pie while it’s cooking.
Bake the pie in two stages. First bake it at 400°F for 30 minutes.
Then place a sheet of aluminum foil over the pie to protect the edges and tops from getting too burnt. (A pie protector is quite useful here.) Reduce the heat to 350°F and bake for an additional 30 minutes, or until the crust has browned and the filling is bubbly.
Remove from oven and place on a wire rack. Cool completely before serving.