Allow the pie crust to come to room temperature while preparing peaches.
Spray 8x8 casserole with butter flavored Pam and set aside.
Combine cornstarch, sugar/Splenda, salt in a small saucepan. Add cold liquid and stir to combine. Cook, stirring over medium-high heat until mixture begins to boil. Cook 2 more minutes to fully thicken. This will seem very thick, but when poured over peaches, it will thin while cooking.
Remove sauce from heat. Add 1 tablespoons butter; stir until melted.
Slice peeled peaches into a large bowl. Stir in sauce. Pour into casserole.
Unroll pie crust on a piece of cling-wrap. Cut into 9 long strips; discard round "ends." Create lattice crust by carefully overlapping strips; alternate folding back vertical strips while adding strips across the horizontal.
Sprinkle lattice top with cinnamon/sugar; dot with more butter if you like.
Bake 10 minutes at 400; Lower heat and continue baking at 350 for 45 minutes.
I like to time the baking of the cobbler so that it emerges from the oven with time to cool while eating & cleaning up from dinner. Add Bluebell Homemade Vanilla Ice Cream and enjoy!