Add Peach (3 pound) to a large bowl. Add the Granulated Sugar (1 cup) and toss until peaches are well coated. Let sit for an hour, so the peaches release their juices.
Lightly flour your work surface and roll one disc of the Pie Crust (2) into a 12 inch circle. Fit it into a 9" pie plate and let the excess hang over the sides. Loosely cover with plastic wrap and refrigerate for 30 minutes -- until dough is firm.
Roll out the other disc of Pie Crust into a rectangle, roughly 12x10". Trim rounded edges and use a ruler to score and slice into even 10" long strips, each about 1" wide. Separate the strips on a cookie sheet and freeze until firm, about 30 minutes.
Preheat oven to 425 degrees F (220 degrees C). Adjust oven rack to the lowest point in your oven. Line a rimmed baking sheet with aluminum foil.
In a small bowl, combine Corn Starch (1 tablespoon), Ground Cinnamon (1/8 teaspoon), Ground Nutmeg (1/8 teaspoon), and Salt (1 pinch). Set aside.
Place a strainer over a medium bowl. Transfer the peaches to the strainer to drain the juices. Reserve 1/4 cup of the juices for the pie. Transfer peaches back to the original bowl.
Add the spice mixture to the peaches, along with the Lemon Juice (1 tablespoon). Toss until well combined.
Spread peaches into the pie crust.
Lay 5 strips of pie crust evenly across the peaches parallel to one another. Weave remaining strips perpendicular to the first ones, to create a lattice crust.
Any excess or hanging dough should be tucked under on itself. Press your thumb and forefinger together and gently place it on the rim of the dough. Use the knuckle on your other hand to crimp the dough. Continue around the circumference of the pie.
Place the pie on the baking sheet. Brush the lattice work and crust with Cream (2 tablespoon) then sprinkle the Demerara Sugar (1 tablespoon) on top.
Mold the tin foil around the perimeter of the pie. Bake for 25 minutes, then turn down the oven to 375 degrees F (190 degrees C).
Rotate the pan halfway to promote even cooking. Cook for an additional 30 minutes, then remove the tin foil.
Cook an additional 10 to 15 minutes.
Cool the pie on a rack until filling has set, about 2 hours. Best served warm or at room temperature.