Prepare the pie dough/crust according the Homemade All Butter Pie Crust recipe up to baking part, or use pre-made pie crust. (See post if you need guidance with rolling out dough or transferring it to your pie plate, or need any pie crust troubleshooting.)
Preheat oven to 400 degrees. Carefully place first pie crust dough into a 9 inch pie dish.
Stir the blueberries, granulated sugar, cornstarch, cinnamon, and lemon juice together in a large bowl. Let filling sit for 10 minutes. Spoon the filling into the crust. Sprinkle the pieces of butter on top of the filling.
Pie Crust Stars: Roll the 2nd pie crust dough out to the desired size (12-13" circle), on a floured surface with a floured rolling pin. Use a star shaped cookie cutter (any size works) to shape into stars. Arrange stars on top of filling.
Make a egg wash, and brush over exposed parts of the crust and the stars. Sprinkle with a little coarse sugar.
Bake for 40-45 minutes, checking the pie at 20 minutes to make sure the crust isn't browning too quickly. If it is, turn the temperature down to 350° and place a piece of foil over the top of the pie and continue baking.
* If using frozen blueberries, the pie will take several more minutes in the oven due to the increased liquid.
Allow pie to cool for 2-3 hours before slicing and serving. Serve with vanilla ice cream !