Pastry: In food processor, pulse flour, salt, butter and shortening until mixture resembles coarse crumbs. With motor running, add lemon juice, then water, 1 Tbsp at a time, just until dough separates from sides of bowl.
Gather dough into a ball and divide in half. Press each half into a disk. Wrap in plastic wrap and refrigerate 1 hour or until firm enough to roll out.
Place a sheet of foil on a rimmed baking pan on bottom rack to catch any juices. Heat oven to 425ºF. Coat a 9-in. pie plate with nonstick spray.
Roll out 1 dough disk on lightly floured surface or between 2 sheets of wax paper to a 12-in. circle. Fit dough into pie plate, pressing gently onto bottom and up sides. Roll out remaining disk as above into an 11-in. circle; cut into 1-in.-wide strips.
Filling: Toss rhubarb and strawberries with vanilla in large bowl. Mix sugar, cornstarch and ginger in a small bowl until blended; toss with berry mixture to evenly coat. Spoon into pastry-lined pie plate; dot with butter.
Arrange 5 dough strips across pie. Arrange remaining 5 strips at right angles, weaving. Press ends into edge, fold under and crimp. Brush strips with water; sprinkle with sugar.
Place pie on center oven rack; bake 25 minutes. Reduce oven temperature to 350ºF, rotate pie 180 degrees and bake 50 minutes more (loosely shield pie with foil if crust gets too brown) until crust is golden and filling bubbles. Cool on wire rack. Serve at room temperature.
Pastry: In food processor, pulse flour, salt, butter and shortening until mixture resembles coarse crumbs. With motor running, add lemon juice, then water, 1 Tbsp at a time, just until dough separates from sides of bowl.
Gather dough into a ball and divide in half. Press each half into a disk. Wrap in plastic wrap and refrigerate 1 hour or until firm enough to roll out.
Place a sheet of foil on a rimmed baking pan on bottom rack to catch any juices. Heat oven to 425ºF. Coat a 9-in. pie plate with nonstick spray.
Roll out 1 dough disk on lightly floured surface or between 2 sheets of wax paper to a 12-in. circle. Fit dough into pie plate, pressing gently onto bottom and up sides. Roll out remaining disk as above into an 11-in. circle; cut into 1-in.-wide strips.
Filling: Toss rhubarb and strawberries with vanilla in large bowl. Mix sugar, cornstarch and ginger in a small bowl until blended; toss with berry mixture to evenly coat. Spoon into pastry-lined pie plate; dot with butter.
Arrange 5 dough strips across pie. Arrange remaining 5 strips at right angles, weaving. Press ends into edge, fold under and crimp. Brush strips with water; sprinkle with sugar.
Place pie on center oven rack; bake 25 minutes. Reduce oven temperature to 350ºF, rotate pie 180 degrees and bake 50 minutes more (loosely shield pie with foil if crust gets too brown) until crust is golden and filling bubbles. Cool on wire rack. Serve at room temperature.