Roll pie pastry out to fit a 9-in pie plate, transfer to plate and crimp edges. Preheat oven to 350F and set aside.
In a large bowl, whisk pumpkin puree, sugar, eggs pumpkin pies spice, salt, cornstarch, vanilla, and milk until smooth. Pour pumpkin filling into prepared crust.
Bake pumpkin pie at 350F 75-80 minutes or until a knife inserted in middle comes out clean. (if necessary, cover crust edges in foil while baking to avoid overbrowning.) Cool pumpkin pie completely on a wire cooling rack.
NOTE: If desired, you can make leaf cut-outs out of leftover pie crust dough and bake them separately from the pie until golden-brown---after the pie is baked, arrange the leaf cutouts on top.