Prepare pie crust dough and refrigerate. After chilling for 30 minutes to 1 hour, divide dough in half and roll out to the shape of the pie plate. Line pie plate and do not remove the overhang. Return to refrigerator to keep everything cold.

Core apples and cut into 1/2" cubes and chop rhubarb into 1/2" pieces. In a large bowl, mix apples and rhubarb with sugar, flour, cinnamon, ginger, salt and lemon juice.

Roll out remaining half of dough. Using a rule as a guide and a ravioli or pasta cutter, cut dough into 1-inch strips.

Preheat oven to 350 degrees F.

Pull bottom crust from the refrigerator and lightly dust with flour. Add filling to mound in plate. Starting from the center, criss-cross and weave the strips of remaining pie dough to form a loose lattice. Fold the edges of the lower crust over the top and neatly crimp both layers into a wave using your knuckles.

Whisk together egg and milk. Brush entire pie with egg wash then sprinkle with coarse sugar. Bake for 60 minutes until the crust is golden brown. Allow to cool and set for at least 20 minutes before serving to allow the juices to set. Enjoy warm or seal tightly to enjoy for days to come.