Lightly flour your surface and unroll 2 of the pie crusts. Place them one on top of the other.Using a rolling pin, roll combined crusts out to a 17x12 inch rectangle. Place in the bottom and up sides of a 15x10 inch sheet pan.
Unroll 3rd pie crust and using leaf shaped cookie cutters, cut out leaves and place on a baking sheet. Re-roll the dough scraps and continue cutting out leaves until all dough has been used.
Place the pie crust pan and leaf cutouts pan into the refrigerator while you are preparing the filling.
For the Filling
In a large bowl, beat the pumpkin, eggs, condensed milk, brown sugar, pie spice and salt until smooth. Spread the mixture into the pie shell and smooth the top.
Place the leaf cutouts on top and around the edges of the sheet pan.
Bake 40-45 minutes, until the crust is browned and the filling is set. Cool completely and slice before serving.