Preheat the oven to 400°F.

Lightly flour a clean work surface. Unroll and stack 3 pie crusts on top of each other. Roll it out into a 12x18 rectangle.

Place the pie crust into a 10x15x1 jelly roll pan and form it into the pan. Trim off some of the excess crust and crimp the edges. Set aside.

In a large bowl whisk together the pumpkin puree, brown sugar, heavy cream, evaporated milk, eggs, vanilla, cornstarch, pumpkin spice, and salt until smooth. Pour into the crust and smooth out the top.

Bake for 28-32 minutes until golden brown on top, the crust is golden brown, and a toothpick inserted into the center comes out clean. Let cool completely on a wire rack.

For optional crust decoration: While the pie is baking, unroll the remaining pie crust onto a lightly floured clean work surface. Using a cookie-cutter, or by hand cut out fall-themed shapes.

Place the shapes onto a parchment paper-lined sheet tray. Beat the egg with a splash of water in a small bowl and brush the crust decorations lightly with the egg wash using a pastry brush. Sprinkle with decorator's sugar.

Bake for 8-10 minutes until golden brown. Cool completely.

Once the pie is cooled to room temperature you can slice and serve with the pie crusts for garnish if using.