3cupsfresh strawberrieshulled and cut into large pieces
Preheat oven to 425.
In a 9 inch pie pan, place one of your pie crusts evenly in the pan and press it into the pan. Set aside in the fridge until the filling is ready.
In a medium bowl, add your chopped rhubarb and strawberries. In a smaller bowl, mix the granulated sugar, brown sugar, cornstarch and salt together.
Pour over the fruit and mix. Add the vanilla, lemon zest and lemon juice and mix again. Pour the filling in the prepared pie shell and dot with butter.
Place the top crust over the filled pie and crimp the edges together. Cut a few vents in the tip crust to allow steam to escape. Use a fork to mix the egg yolk and water together and with a pastry brush, brush it evenly across the top crust. You may sprinkle some granulated sugar or coarse sugar crystals over the top for added texture and sweetness.
Place pie on a baking sheet lined with parchment (this will prevent spills in your oven if the pie bubbles over) and bake on the middle rack for about 45-50 minutes, until the filling is bubbling and the top crust is very golden brown. If the crust is getting too dark before the time is up, cover it gently with foil to avoid burning the top crust while the bottom crust bakes through.