Blueberry Slab Pie

Looking for a dessert for your 4th of July picnic? Slab pies are the answer!  They serve a lot of people, you can eat them by hand, no plate, just a napkin. It's a nice surprise not to have to think about your blueberry pie being a little runny....this one holds together nicely. And frankly, I think making slab pie crusts are easier than making a regular pie crust. Almost like a galette: just tuck those edges under. No fuss.
If you have paper plates on hand, you could serve them on a plate as well, with a scoop of your favorite ice cream. For the 4th, I chose blueberries for this slab pie, but I've made peach and apple as well. I just think a blueberry pie goes better with the July 4th celebration.

HAVE A HAPPY AND SAFE 4TH EVERYONE!

Blueberry Slab Pie

Ingredients:
For the crust:
5 cups all-purpose flour, plus more for rolling
1 1/2 teaspoons coarse salt
2 tablespoons sugar
2 cups (4 sticks) cold unsalted butter, cut into small pieces
1 to 1 1/2 cups ice water

For the filling:
2 1/4 pounds fresh blueberries (8 cups)
3 tablespoons cornstarch
1/2 cup plus 2 tablespoons sugar
1 tablespoon grated lemon zest, plus 2 tablespoons lemon juice
good dash of cinnamon, maybe even a scrape of fresh nutmeg

Method:
Make the crust:
In your food processor, pulse flour, salt, and sugar a couple times. Add butter; pulse until mixture resembles coarse meal. With machine running, add 1 cup ice water. Pulse until dough is crumbly but holds together when squeezed. You can add more water in tablespoon increments, but just until dough holds together...do not overmix. Divide dough in half, wrap in plastic and refrigerate until firm or overnight.
Preheat oven to 400 degrees.
On a floured surface, roll out the first disk to a 12-by-16-inch rectangle. Place in a 10-by-14-by-1-inch rimmed jelly-roll pan. 

Make the blueberry filling:
Toss together blueberries, cornstarch, sugar, cinnamon, lemon zest and juice. Pour evenly over the unbaked bottom crust.
On a floured surface, roll out second disk to an 11-by-15-inch rectangle. Moisten the edges of the bottom crust with water. Lay the second piece of pastry over the blueberry filling; press along moistened edges to seal. (The bottom is bigger than the top, so I fold the bottom crust over the top and crimp to seal so the blueberries don't run out while baking.) 
Make some slices in the top, cut out some small stars or you could even do a lattice top crust if you like.
Brush with egg wash, sprinkle with a bit of sugar.
Place pie in the oven, reduce heat immediately to 375 and bake for about 50 minutes until crust is golden and blueberries are bubbling.
Cool at least an hour before slicing.