"I use tapioca flour mixed with sugar to thicken the berries. The filling will thicken upon cooling, so try not to cut into pie until completely cool."
1Mix tapioca flour and sugar together, and blend mixture into the berries.
2Line a pie dish with pastry. Pour filling into pie shell, and cover with top crust. Seal edges by pinching or fluting the edge. Brush top with egg white and sprinkle with a little sugar. Cut slits in top to allow steam to escape.
3Bake at 350 degrees F (175 degrees C) for 30 to 40 minutes, until pie is golden brown and bubbly.