Preheat your oven to 400 degrees F and place an oven rack to the bottom third of the oven.
Remove one pie shell from the freezer to thaw on the counter, leaving it in the pie plate for now.
Whisk together the sugar, cornstarch, cinnamon nutmeg, and salt in a medium bowl. Set aside.
Rinse and dry the blueberries, and then transfer them to a large mixing bowl. Mix in the lemon juice and lemon zest. Sprinkle the sugar mixture over the blueberries and mix until coated.
Take the second pie crust out of the freezer. Pierce the bottom with a fork and then pour the blueberries into the crust. Spread them into an even layer.
Remove the thawed pie crust from the plate and place it onto a lightly floured work surface. Roll out the crust a bit to flatten it out (you don't want it too thin). Use different size star cookie cutters to cut out the dough. Place the stars over the blueberry filling in an arrangement of your choice, brushing the dough stars with beaten egg as you lay them on to help glue them together. (see note)
Crimp any star pieces touching the bottom crust to it with a fork. Sprinkle the stars with raw sugar, if desired. Place the pie on a cookie sheet lined with parchment paper or a silicone mat. (The filling will overflow a bit and this makes for easy clean up.)
Bake at 400 degrees F for 15 minutes. Then lower the oven temperature to 350 degrees F and bake for an additional 50 minutes until the filling is bubbling and the crust is golden brown.
Once the pie has baked, transfer it to a wire rack to cool for 2-3 hours. The longer it sits the thicker the juices in the filling will become. Cut into 8 slices and serve.
Notes
If you prefer to use homemade pie crust you absolutely can. You'll need 2 crusts large enough to cover a deep-dish pie plate.
If you don't want to make a star crust design, you can lay the thawed crust over the blueberries and crimp the edges to the bottom crust. Then cut some slits into the top crust to allow steam to escape during baking.