Preheat oven to 400 degrees F.
Prepare pie pastry. Learn how to make different types of Pie Pastry for 9-inch two-crust pie.
In a large bowl, combine blackberries, sugar, tapioca, cinnamon, and lemon juice. Spoon into pastry-lined plate.
Cover with remaining pastry and flute. Cut slits in pastry so steam can escape. Cover edge with aluminum foil to prevent excessive browning.
Bake 10 minutes; reduce heat to 375 degrees F. and bake approximately an additional 35 to 40 minutes or until the internal temperature registers approximately 175 degrees F. on your cooking thermometer and the crust is nicely browned and the filling is set. Remove aluminum foil during last 15 minutes of baking.
Remove from oven and cool on a wire rack before cutting and serving.
Serve warm or at room temperature.
Oregon Blackberry Pie Recipe: https://whatscookingamerica.net/blkbrypie.htm