Place the flour, salt, and sugar into a food processor and pulse until well combined.

Add half of the butter cubes and pulse 8 times. Then add the other half of the butter cubes and pulse 6 more times. You should have a mixture that resembles a coarse meal, with many butter pieces the size of peas.

Slowly add ¼ cup of ice-cold water (without the ice!) to the food processor bowl and pulse several times. Then add more ice water, slowly, a tablespoon at a time, pulsing several times after each addition, until the mixture just barely begins to clump together. If you pinch some of the crumbly dough and it holds together, it's ready, if not, add a little more water and pulse again.

Use your hands to press the crumbly dough together and divide into four equal-sized disks. Work the dough only enough to just bring the dough together. Do not over-knead or your crust will end up tough.

You should be able to see little bits of butter, speckling the dough. When these bits of butter melt as the crust cooks, the butter will help separate the dough into flaky layers. So, visible pieces of butter are a good thing, what you are aiming for, in the dough.

Wrap the disks in plastic wrap and refrigerate at least 1 hour.

(At this point you can freeze the dough for a month until ready to use. Defrost overnight in the refrigerator before proceeding.)

Preheat oven to 350° F.

Remove the dough disks from the refrigerator and let it sit for 10 to 15 minutes to take enough of a chill off of it so that it becomes easier to roll out.

Mix the berries, sugar, flour and lemon juice together in a bowl. Let the berries sit while you roll out your crust so they can form a bit of a syrup.

While the dough disks are still wrapped in plastic, warm the edges with your hands. If there are any cracks in the dough, massage them to close them.

Place the dough disk on a lightly floured, clean flat surface. Sprinkle some flour on top of the disk.

Roll each disk out into a circle of ¼” thickness (it will be bigger than your pie dish). Turn your pie dish upside down in the middle of the dough circle and cut around it 1-inch away from the edge of the pie dish. Place in individual pie/tart pans and gently press into place. Trim edges even with the edge of the pie dish if necessary.

Take trimmings and bring together into a disk. Roll out and use a pizza cutter or bench scraper to cut out strips ½” wide and about 6” in length. Set aside.

Divide the berry mixture evenly between the pie crusts.

Place the strips of pie dough over the top of the pie in an overlapping basket-weave pattern. Trim the strip ends so they are even with the edge of the pie dough. Press the ends gently into the edge of the pie dough.

Brush the crust with the egg mixture and sprinkle with the demerara sugar (optional).

Place the pies on a foil or parchment lined baking sheet (in case the filling bubbles over).

Bake for 35-40 minutes. If the crusts look like they are getting too brown, cover with foil for the remainder of the bake time.