5 c flour, plus more for rolling
2 T sugar
1 t salt
2 c cold unsalted butter, cut into 1/2-inch pieces
1 c ice water
Make crust: In a food processor, pulse flour, sugar and salt until combined. Add butter and pulse until mixture resembles coarse meal, with a few pea-size pieces of butter remaining. With machine running, add 1 c water. Pulse until dough is crumbly but holds together when squeezed; DO NOT over mix. Divide dough into 2 disks, wrap each tightly in plastic, and place in refrigerator until firm, for 1 hour or overnight.
6 c strawberries, hulled and halved
6 c rhubarb, cut into 3/4-inch pieces
3/4 c sugar
1/3 c light brown sugar
1/3 c quick-cooking tapioca
1 1/2 t grated orange zest, plus 2 T orange juice
2 egg yolks, lightly beaten with 2 t water
1/3 – 1/2 c sanding sugar (optional)
Preheat oven to 400 degrees. Prepare filling- In a bowl, toss together strawberries, rhubarb, sugar, brown sugar, tapioca, zest and juice.
On a lightly floured work surface, roll out 1 disk to a 12 x 16 inch rectangle. Place dough in a 10 x 14 inch pan. Press gently to fit into pan and spread fruit mixture over crust. Roll out remaining disk to an 11 x 15 inch rectangle. Place over filling, pressing along edges to seal. Trim edges of dough, leaving 1 1/2 inch overhang all around. Fold overhang under, crimp edges. Brush entire crust with egg-yolk mixture and sprinkle with sanding sugar, if desired.
Cut slits in top crust to vent. Place pan in oven, reduce temperature to 375 degrees. Bake until crust is deep golden brown and juices are bubbling in center, 55 to 65 minutes. Cool on a wire rack for 1 hour. Serve warm or at room temperature.
