Make Two Layer Crust:
1.
Combine the flour, sugar, cinnamon and salt in the bowl of a food processor, pulsing to combine. Add in the butter and pulse until butter is the size of peas. Add in the vanilla and water, pulsing again just until the dough comes together, adding more water by the tablespoon if necessary.
2.
Gather dough into a ball divide into two and flatten into a disk, wrap in plastic wrap or place in zip bag. Refrigerate for at least 30 minutes and up to 24 hours.
Make Filling:
3.
Mix the rhubarb, strawberries, sugar, cornstarch, cinnamon and nutmeg in a large heavy saucepan. Allow to macerate for 30 minutes, stirring occasionally.
4.
Bring to a boil over medium heat, stirring constantly. Reduce the heat and simmer until juices thicken, about 3 minutes. Allow to cool while preparing rest of pie.
Prepare Pastry:
5.
Roll out one pastry disk to a 12-Inch square that is 1/8-Inch thick on a lightly floured surface. Cut into 1/2-Inch strips with a pastry wheel or knife. Transfer strips to a sheet of parchment paper and cover. Place in refrigerator while preparing bottom pastry sheet.
6.
Roll out the second pastry disk to a 12 inch by 1/8-Inch thick between two sheets of parchment paper. Peel off the top sheet of paper. Transfer the dough to a 9-inch deep dish pie plate. Discard the paper. Trim the overhang to 1/2-inch and crimp edges if desired. Refrigerate 20 minutes.
7.
Preheat oven to 350°F. Line the crust with parchment paper or foil. Fill with dried beans or pie weights. Bake until the crust is set, about 15 minutes. Remove the paper and beans. Cool 5 minutes and brush the crust with the egg glaze.
Pie Construction:
8.
Increase oven temperature to 375°F. Pour the filling into the prepared crust, dot with 2 tablespoons butter. Weave strips into a lattice; cover filling. Turn ends under just enough so those strips touch sides of baking dish; crimp edges. Brush lattice top with milk; sprinkle with sugar.
9.
Bake in 375°F for 40 minutes, or until pastry is golden and juices bubble up; cool. Serve warm with vanilla ice cream if you wish.
Tip:
10.
If using frozen rhubarb, measure rhubarb while still frozen, then thaw completely. Drain in a colander, but do not press liquid out.
11.
I like to use the crust trimmings up by balling them up and refrigerate for 30 minutes then re-rolling to 1/4 - 1/8 Inch thick, sprinkle with cinnamon sugar and cutting into strips. Bake with pie and remove from oven when crispy. Makes for a treat for the kiddies, pint sized or full sized. (wink, wink)