Lightly flour the surface you will be using. Roll out the pie crust with a rolling pin to a 10 to 12-inch circle.
Using a pizza or a pastry cutter, cut 1-inch wide strips. You will need 10 of the strips, 5 each for the vertical and horizontal strips.
Starting at the center of the pie, lay down one of the longest strips and place the shorter strips closer to the edges.
Fold the second and fourth strips halfway back. Lay 1 of the longer strips in the center. Unfold the 2 strips.
Fold back the first, third, and fifth strips back in the same direction as the second and fourth strips. Lay another strip and unfold the strips like the previous strips.
Fold the second and fourth strips for the final strip of dough on this side. Unfold the second and fourth strips. Turn the pie around and repeat the previous weave of pie strips.
Once the lattice is woven, trim the overhanging dough about a ½ inch all the way around.
Roll the edges of the overhang, slightly pinching the dough together as you roll to help seal the lattice and bottom crust.
Using your index finger and thumb on one hand and the thumb or index finger of the other hand, begin to crimp the edges for a nice finishing touch.
In a small mixing bowl, whisk together the large egg and cold water until completely combined.
Brush the egg wash onto the edges and all over the lattice top with a pastry brush.
Place the pie on a cookie sheet lined with foil for easy cleanup in case the pie bubbles over while baking.
Bake for 1 hour to 1 hour 15 minutes, or until the top and bottom crust are golden.