2 pounds strawberries, hulled and halved or quartered depending on size
2 pounds rhubarb, cut into 3/4-inch pieces
2/4 cup granulated sugar
1/3 cup packed light brown sugar
1/3 cup quick-cooking tapioca
1–1/2 packed teaspoons grated orange zest, plus 2 tablespoons orange juice
2 large egg yolks, lightly beaten with 2 teaspoons water
1/3 to 1/2 cup sanding sugar
For the crust, pulse the flour, sugar and salt in a food processor. Add the butter and process until the mixture looks like coarse meal with a few pea-sized pieces of butter. With the motor running, pour in the ice water and continue processing until the dough forms. Divide the dough in half and pat into round disks. Wrap them in plastic wrap and chill in the refrigerator until firm, 1 hour or up to overnight.
Preheat the oven to 400 degrees F.
To make the filling, combine the strawberries, rhubarb, granulated sugar, brown sugar, tapioca, orange zest and juice in a large bowl.
Roll out one disk of dough on a lightly floured work surface with a floured rolling pin to a 12-inch-by-16-inch rectangle. Transfer the dough to a 10-inch-by-14-inch jelly-roll pan pressing the dough into the pan. Spread the filling into an even layer.
Roll out the remaining dough on a lightly floured work surface to a 12-inch-by-16-inch rectangle. Place the dough on top of the filling. Trim the edges leaving a 1-1/2-inch overhang and tuck it under in the pan. Brush the top with the egg yolk-mixture and sprinkle with sanding sugar. Use a pairing knife to cut slits in the dough to vent. Put the pie in the oven and reduce the oven temperature to 375 degrees F. Bake for 55 to 65 minutes until the crust is golden brown and the filling is bubbling. Cool for at least 1 hour on a wire rack. The pie can be served warm or at room temperature.