In a food processor, combine all the dry ingredients, pulse until combined. Add in the butter and shortening, pulse until it resembles bread crumbs. Add the ice water in 3 stages, until the mixture comes together and forms a ball. You may need more or less depending on the mixture- if it still looks dry, add more water- it is important to add it gradually.

If there are small chunks of butter, it is alright, it makes the tart even flakier.

Place the dough on a floured work surface, and divide in into two balls. Form disks, and wrap in plastic. Refrigerate at least 1 hour before using. (I usually make the dough the day before.)

Position a rack in the lower third of the oven and preheat the oven to 425 degrees F.

Put the berries in a large bowl and gently stir in the sugar, flour, salt, zest and juice; let sit for about five minutes. Taste the filling and add more sugar and/or lemon juice, if you want.

Sprinkle an even layer of the cookie crumbs over the bottom crust. Give the filling a last stir and turn it into the crust.

Unwrap the disks, and flour a work surface. (For this part, I use two large squares of parchment paper, and place the dough between them. Use a lot of flour to keep the dough from sticking.)

Roll the dough out to about 0.5 cm thickness, it should be fairly wide. Carefully place the dough in the middle of a 9×13 pie plate, and cut off the extra bits.

Roll the second disk out and keep it ready.

Using your fingertips, moisten the rim of the bottom crust with a little cold water. Center the top crust over the filling and gently press it against the bottom. Seal, trim and either flute or press the edges of the crusts together.

Using a small knife, cut 4 slits in the top crust and cut a circle out of the center. Put the pie plate on a baking sheet lined with parchment paper or a silicone baking mat – it will be your drip-catcher. (If you have time, refrigerate the pie for about 30 minutes. The pie can also be wrapped airtight and frozen for up to 2 months. Glaze and sugar it before you put it in the oven and add at least 15 minutes to the baking time.)

Brush the top crust with the egg wash then sprinkle the crust with a little sugar – just to give it sparkle.

Bake the pie for 30 minutes.

Reduce the oven temperature to 375 degrees F, and bake the pie for another 30 minutes or so (total baking time is about 1 hour), or until the crust is a beautiful golden brown and the filling is bubbling up through the slits. If the crust seems to be browning too quickly, make a loose foil tent for the pie.

Transfer the pie to a rack and let it cool – and settle – for at least 30 minutes before serving.