2¼ cups all-purpose flour
1 Tablespoon sugar
½ teaspoon salt
1 cup (2 sticks) cold unsalted butter, cut into small pieces
2 teaspoons raspberry vinegar
6 tablespoons ice cold water
In a large bowl, whisk together the flour, sugar and salt. Using a bench scraper or your fingertips, cut in the butter pieces until the mixture is crumbly with pieces of butter about the size of a pea. Combine the vinegar with the water. Gradually add the liquid to the flour/butter mixture, tossing it until the dough is somewhat shaggy and just holds together. Turn the dough out onto a lightly floured sheet of parchment paper, gather it into two discs, flatten them slightly and wrap each in plastic wrap. Refrigerate for at least one hour before rolling out. Roll out one disc of dough to a thickness of about ⅛" and place it in a 9" pie plate. Roll and crimp the edges. Refrigerate the bottom crust. Roll out the second disc of dough to a thickness of about ⅛" and trim it to a diameter of 12". Refrigerate the top crust while you prepare the filling. (If you wish to use a lattice for the top crust, cut the top crust into 1" strips.)
Raspberry Rhubarb filling
1 pound fresh or frozen rhubarb, rinsed, leaves removed, cut into ½" pieces (about 2½ cups)
2½ cups fresh raspberries
1 cup sugar
2 teaspoons orange zest
pinch of freshly grated nutmeg
⅛ teaspoon cardamom
3 tablespoons instant tapioca, finely ground
egg wash made from 1 egg yolk beaten with 1 tablespoon milk or heavy cream
coarse sanding sugar for sprinkling
Preheat the oven to 425 degrees F.
In a medium bowl, whisk together the sugar, orange zest, salt, nutmeg, cardamom and tapioca. Place the rhubarb in a large bowl. Add the sugar mixture, tossing to coat. Gently fold in half of the raspberries; reserve the remaining raspberries. Turn the filling into the bottom crust, add the remaining raspberries, and drape the top crust over the filling.* Seal, trim, fold and crimp the edges. Cut steam vents in the top crust, brush with the egg wash and sprinkle with the sanding sugar.
Place the pie on a parchment lined baking sheet. Bake on the bottom rack of the oven for 20 minutes until the crust is set and begins to turn golden. Reduce the oven temperature to 375 F. Move the pie on its baking sheet to the middle rack and bake for an additional 45 minutes, until the crust is toasty brown and juices bubble thickly around the edges and through the pie vents. Remove from the oven and set on a rack to cool for at least 3 hours before slicing. Wrap and refrigerate any leftovers.
(* a lattice crust can be made by slicing the refrigerated top crust into 1" strips and weaving them over the filling. Seal, trim, fold and crimp the edges as you would for a double-crusted pie.)