Preheat oven to 425ºF while allowing pie crusts to sit at room temperature for 10-15 minutes. 

Carefully unroll one of the crusts onto 9″ pie plate then unroll second crust onto large cutting board.

Using decorative pie crust cutters or a small cookie cutter, cut shapes out of crust. Alternatively, you could cut the crust into strips to do a lattice-type crust.

Add sugar, cornstarch, salt and cinnamon to blueberries; carefully mix together until blueberries are evenly coated.

Pour blueberries into pie crust; cut butter into several pats, then arrange pats over top of blueberries.

Cover blueberries with second pie crust. Crimp edges together, then place cutout shapes over top of crust.

Whisk together egg yolk and heavy cream; brush over pie crust.

Place pie on cookie sheet and bake for approximately 50 minutes at 425ºF. (You may want to cover pie with foil after 20-25 minutes so that it doesn’t get too brown.)