All-butter double crust pie pastry:
2¼ cups all-purpose flour
1 teaspoon salt
1 tablespoon sugar
7 ounces cold, unsalted butter, cut into ½” cubes
5-6 tablespoons ice cold water
1 tablespoon cider vinegar
Place the flour, salt and sugar together in a large bowl; whisk to combine. Using a pastry cutter or your fingers, add the cold butter blending it into the flour until it resembles coarse meal. Sprinkle 5 tablespoons of ice cold water and the tablespoon of vinegar onto the flour/butter mixture. Toss the mixture using a fork or your fingers, mixing just until the dough comes together. (If the mixture feels dry, add up to an additional tablespoon of water.) Divide the dough in half, shape each half into a disc and wrap each half in plastic wrap. Refrigerate for at least an hour before rolling out.
On a lightly floured sheet of parchment paper, roll out one portion of the dough into a circle about 12” in diameter and about ⅛” thick. Gently place the dough into a 9” pie plate, being careful not to stretch it. Trim the excess dough so you have a 1” overhang. Place the bottom crust in the refrigerator. Roll out the second half of dough for the lattice top on a lightly floured sheet of parchment paper into a circle about 10” in diameter and about ⅛” thick. Use a pastry cutter or a knife to cut ten 1” wide lattice strips. Carefully slide the parchment paper with the lattice strips on to a baking sheet and put it back in the refrigerator to chill while you prepare the filling.
Prepare the egg wash - 1 egg beaten with 1 teaspoon of water and set aside with coarse sugar for sprinkling.
1½ pounds rhubarb, rinsed, leaves removed, trimmed and coarsely chopped (you will need 3½ cups)
1 quart fresh strawberries, lightly rinsed, stems removed, cut in quarters (you will need 3½ cups; save any extras for another use)
2 teaspoons fresh orange juice
1 teaspoon fresh lemon juice
1 teaspoon good quality vanilla
1 cup sugar
2 tablespoons dark brown sugar
¼ teaspoon freshly ground cardamom
¼ teaspoon cinnamon
1 teaspoon orange zest
¼ cup finely ground instant tapioca
In a large bowl, toss just the rhubarb with the orange juice, lemon juice and vanilla. In a small bowl, whisk together the sugars, salt, cardamom, cinnamon, orange zest and tapioca. Add the sugars/spices/tapioca to the rhubarb and let it sit for 30 minutes to soften the tapioca and the rhubarb. (Save the strawberries; you will add them later.)
Preheat the oven to 425 degrees F. Retrieve the pie plate with the bottom crust from
the refrigerator and the baking sheet with the lattice crust strips. Add the strawberries to the rhubarb mixture, using a rubber spatula to gently combine. Place the pie plate on a baking sheet lined with parchment paper and pour the filling into the pie shell. Brush the top side of the overhanging dough with a little of the egg wash. Place one lattice strip in the center of the pie, then another strip perpendicular to the first strip, forming a “t”. Add the remaining strips to create a lattice. Trim the edges so they are no longer than 1 inch over the pie pan’s edge. Lift the overhanging dough onto the top crust, roll and seal the edges together, crimping with your fingers so you have a standing edge. Carefully brush the lattice with the egg wash, sprinkling with coarse sanding sugar. Place the pie on a parchment lined baking sheet and bake it on the bottom rack of the preheated oven for 15 minutes. Rotate the baking sheet and bake for an additional 15 minutes at 425 degrees. Then reduce the oven temperature to 375 degrees and continue baking for an additional 40 to 45 minutes, covering the edges of the pie with strips of aluminum foil to prevent overbrowning. The pie will be golden and the fruit will bubble around the edges and in the center of the pie when it is ready. Remove from the oven and place on a cooling rack. Cool for several hours before slicing. Refrigerate any leftovers.