To prepare the pie crust:
- Give the dry ingredients a whiz in the food processor to combine.
- Pulse in the unsalted Kerrygold butter, just until evenly dispersed and pea-sized clumps form.
- Add in 6 or 7 tablespoons of ice water and pulse, adding in an additional tablespoon of water until a dough begins to form. I usually need 9-10 tablespoons of water.
- Remove dough from food processor and separate in two round disks. Wrap in Saran wrap and chill for at least 30 minutes prior to use.
To prepare the pie filling:
- Combine the lemon juice, zest, and berries in a large bowl.
- Add the flour, cinnamon, and sugar and toss to combine evenly. Set aside while you make assemble your pie.
To assemble your pie:
- Preheat an oven to 375 degrees.
- Prepare an egg wash by whisking 1 egg with 2 teaspoons of water. Set aside while you prepare the pie.
- Roll out one half of your dough on a lightly floured surface to a 12”x17” rectangle.
- Once smoothed and sized, roll the dough back onto the rolling pin and transfer the dough into a 15″ x 10″ x 1″ jelly roll pan.
- Gently press the dough into the edges of the pan and trim off excess dough, leaving a 3/4’” overhand around all edges. Use some excess dough to fill in spots where the dough may have cracked or wasn’t long enough.
- Sprinkle your prepared fruit into the pan and spread out to fill evenly. Roll out your remaining piece of dough to a 12”x17” rectangle.
- Roll the dough onto your rolling pin and transfer it to the pie. Center the pie top on the pan and fold the bottom edge over the top, crimping with your fingers as desired.
- Use a knife to vent the pie and brush the egg wash over the top crust. Bake in the preheated oven for 50-60 minutes, or until the top is golden brown and the filling inside is bubbling.
- Rotate the pie during baking as needed to brown evenly.