Preheat the oven to 425°.
Place 1 rolled out pie crust into the pie plate.
Mix the blueberries with the sugar, tapioca, and cinnamon
Cut the butter into small pieces, and place them on top of the blueberry filling.
Roll the remaining dough, fold it in half gently place it over the filled pie, and unfold it so it nicely lays on top.
Trim the edges of the crust so they are both even. Leaving one-inch of crust past the edge of the pie plate
Flute the edge of the pie dough, then cover the edges with strips of foil.
Brush the top of the pie crust with some heavy cream or milk to brown the crust a bit.
Make 4 small cuts with a knife for the steam to release as it bakes.
Bake at 425° preheated oven. Bake until some blueberry juice starts bubbling.
Bake pie in the center of the oven.
Set timer 50 minutes, and test every 5 minutes till done (mine takes 1 hr. 5 min.)