For the crust
1 1/2 cups ground almonds (may substitute almond meal or almond flour)
2/3 cup confectioners' sugar, plus more for dusting
1/3 cup potato starch
4 tablespoons unsalted butter, or coconut oil or margarine, frozen for 30 minutes and then cut into pieces
1 tablespoon cold water
1 large egg, separated into yolk and white
1/4 teaspoon vanilla extract (optional)
For the filling
4 cups fresh blueberries, stemmed and rinsed
1/2 cup granulated sugar, plus 1 teaspoon for sprinkling
1/2 teaspoon ground cinnamon
1 teaspoon finely grated lemon zest (from 1 lemon)
3 tablespoons potato starch
For the crust: Combine the ground almonds, confectioners' sugar and potato starch in a food processor; pulse for 10 seconds to blend.
Add the frozen butter, coconut oil or margarine pieces; process until the mixture resembles coarse sand.
Add the water, egg yolk and vanilla extract; process just until a dough comes together, being careful not to over-mix.
Gather into a ball and flatten, then break off a little more than one-third of the dough.
Wrap both pieces of dough separately in plastic wrap and flatten into disks. Chill in the freezer for at least 2 hours, or up to overnight.
Remove the larger piece of dough from the freezer and let it defrost until you can press it gently.
Place on a piece of parchment paper sprinkled with confectioners' sugar.
Sprinkle the top of the dough with some more confectioners' sugar and cover with a piece of parchment.
Roll the dough into a 10-inch round. Peel back the top parchment and sprinkle confectioners' sugar on the dough as you roll.
Once or twice, flip over the package of parchment and dough, peel off the bottom and sprinkle some more confectioners' sugar on top.
Re-cover with parchment and flip back over.
Remove the top parchment. Place your hand under the bottom parchment, lift the dough and invert it into the pie pan.
Use your hands to gently press and fit the dough to the pan. Remove the remaining parchment (which is now on top).
Use a knife to trim the dough, then patch up any bare or thin spots, and use a fork to prick the dough in several places.
Reserve any dough scraps for additional cutouts that will form the top crust.
Cover the pie shell with plastic wrap and freeze until you're done with the filling, or up to several days.
Roll the reserved scraps between two pieces of parchment to a thickness of about 1/3 inch thick, then remove the top parchment and cut out the shapes.
Unwrap the remaining piece of dough (from the freezer) and repeat the same step to make more dough cutouts; you'll need a total of about 20.
Place them on a lined baking sheet and freeze until firm.
For the filling, make sure there are no stems on the blueberries.
Place 3 cups of them in a stain-proof mixing bowl. Use a potato masher or large fork to break them down a bit. (Be careful not to make them too soupy.)
Add the sugar, cinnamon, lemon zest, salt and potato starch, stirring to incorporate. Gently mix in the remaining cup of berries.
Preheat the oven to 350 degrees.
Remove the bottom pie crust shell from the freezer and place on top of a baking sheet lined with parchment paper or a silicone liner.
Spread the filling evenly in the pie crust shell. Remove the dough cutouts from the freezer; use a thin metal spatula to transfer them one by one on top of the filling, in a decorative pattern that does not completely cover the filling.
Use a pastry brush to brush the remaining egg white over the dough cutouts atop the pie, then sprinkle the remaining teaspoon of granulated sugar all over. Bake (bottom rack) for 55 minutes to 1 hour, or until the top crust cutouts are golden and the filling is bubbling.
If the edges of the cutouts or edge of the pie seem to be getting too brown before the pie is done, crimp aluminum foil loosely over them.
Cool for at least 1 hour before serving or storing.
The Washington Post