Stir cornstarch into orange juice (or water) until fully dissolved.
Combine all pie filling ingredients (except for butter) in a large bowl and mix gently to combine.
Prepare pie crust. Roll out top and bottom crust between two sheets of waxed paper. Place bottom crust into 9" pie plate.
Mound filling into bottom pie crust. Add dots of butter evenly over pie filling.
Add top pie crust, cut slits for a steam vent and crimp edges to join top and bottom crust. Or, cut the top pie crust into strips and lay across the top of the pie, weaving strips over and under each other to form a lattice crust.
Brush with milk, water, or vodka and sprinkle with granulated sugar (for a sugary crust) OR brush with a mixture of 1 egg yolk +1 tsp. water (for a shiny golden crust).
Protect the crust with aluminum foil around the edges.
Bake at 425 degrees for 30 minutes. Remove the aluminum foil from the crust and continue baking another 10-15 minutes until the crust is browned and the pie filling is bubbly.
Let pie cool completely before slicing. Serve with vanilla ice cream or whipped cream.
Notes
After making this strawberry rhubarb pie many times, I have found that every now and then, even though I'm using the same recipe, my pie filling doesn't set. I think it probably has to do with the water content in either the strawberries or rhubarb.I now add cornstarch to the recipe also so that I never end up with a runny pie. Mix a couple tablespoons of cornstarch into a small amount of orange juice or water until it is dissolved. Pour this mixture in with the rest of the pie ingredients. A couple tablespoons of instant tapioca also works well to ensure a good set to the pie.Adding some dabs of butter over the pie filling reduces foam and adds delicious flavor and richness.