Nothing says summer like blueberry pie. The filling is quick and simple to prepare, and if you have access to good-quality frozen pastry rounds, this dessert will go together in a jiffy.
Roll out one pastry round into a 10-inch circle and line a 9-inch pie pan with the dough, leaving a half-inch overhang. Brush the bottom and sides of the dough with the egg white and then refrigerate the pastry for at least 30 minutes to dry the egg white. This will help seal the bottom crust.
Place the sugar, cornstarch, salt, nutmeg, and lemon zest in a large bowl, and whisk to combine. Add the blueberries and lemon juice, and toss to combine. Let the fruit rest for 10 minutes, then drain off any accumulated juices.
Roll out the top crust into an 11-inch round. Sprinkle the cookie crumbs over the bottom of the chilled pie dough. Add the blueberry filling and then place the top pastry round over the filling. Trim the dough edges evenly, allowing for a one-inch overhang. Tuck the top pastry edge under the bottom crust and crimp together decoratively to make a sealed edge. Cut several steam vents in the top crust. Freeze the pie for 15 minutes before baking.
Position a rack in the lower third of the oven and place a rimmed baking sheet on the rack. Preheat the oven to 425 degrees F.
Place the pie on the preheated baking sheet and bake for 20 minutes. Reduce the oven temperature to 350 degrees F and cook until the pie juices start to ooze out around the edges and bubble out of the steam cuts, 30 to 40 minutes more. Cool the pie in the pan on a wire rack for 2 hours before serving.