Make the a double crust pie dough
of your choice.
Preheat oven to 425F.
Put berries, sugar, nutmeg, salt and tapioca into a bowl, mix and set aside.
Roll out one dough and place in pie pan. Pour filling into dough and set aside.
Beat egg white and 1 tablespoon water together in a bowl and set aside.
Roll out remaining dough and cut into 3/4"-wide strips. Arrange strips over pie in a lattice pattern. Trim off the excess dough and crimp edges of pie.
Brush the crust with egg white mixture and sprinkle with an extra teaspoon or two of sugar.
Bake for 15 minutes at 425F then reduce heat to 350F. Bake about 30-35 minutes more or until the top is golden brown and there is steady bubbling coming through the vents.
Let cool before serving.