Prepare one disc of pie crust in a 9 inch pie pan.
Combine the raspberries, sugar, cornstarch and tapioca in a large bowl and stir to coat. Let sit for 15 minutes, then pour into the prepared pie pan.
Top your pie with the remaining rolled out pie dough. If you would like to cover the pie completely, remember to cut a few slits in the top so the fruit can vent.
Brush the top of the pie dough with the lightly beaten egg and sprinkle with the remaining sugar. Bake in a preheated 350 degree F oven for 50 to 55 minutes, or until the center is lightly bubbling and the crust is golden brown.**
Let cool completely on a wire rack. Slice and enjoy!
*If using frozen raspberries, increase the amount of cornstarch to 3 tbsp.**If the crust is browning too quickly, you can loosely cover the crust with tinfoil and continue baking until the center is bubbly.