Finnish Blueberry Pie

Instructions

1. Prepare the dough
   In a large bowl, combine flour, sugar, and baking powder. Add the cold cubed butter and use your fingers or a pastry cutter to work it into the flour until the mixture resembles coarse crumbs. Add the egg and vanilla extract, then mix until the dough comes together. Don't overwork it. Shape into a ball, wrap in plastic, and refrigerate for 30 minutes.
2. Prepare the filling
   In a medium bowl, gently toss the blueberries with sugar, potato starch (or cornstarch), ground cardamom, lemon zest, and lemon juice. Set aside to allow the flavors to meld while the dough chills.
3. Shape the crust
   Preheat your oven to 375°F (190°C). Remove the dough from the refrigerator. Set aside about 1/3 of the dough for the lattice top. Roll out the remaining dough on a lightly floured surface to fit a 9-inch (23cm) tart pan or pie dish. Press the dough into the bottom and up the sides of the pan. Prick the bottom several times with a fork.
4. Add the filling
   Pour the blueberry mixture into the prepared crust, spreading it evenly.
5. Create the lattice top
   Roll out the reserved dough and cut it into strips about 1/2 inch (1.3cm) wide. Arrange the strips in a lattice pattern over the filling, or simply crumble the dough over the top for a more rustic look. If making a lattice, weave the strips over and under each other for a traditional appearance.
6. Bake the pie
   Place the pie on a baking sheet (to catch any juices that might bubble over) and bake in the preheated oven for 35-40 minutes, or until the crust is golden brown and the filling is bubbling. If the edges start to brown too quickly, cover them with aluminum foil.
7. Cool and serve
   Remove the pie from the oven and let it cool on a wire rack for at least 1 hour before serving. This allows the filling to set properly. Serve at room temperature or slightly warm, optionally with a dollop of whipped cream or vanilla ice cream.