Prep the puree: Take 1 heaping cup of peeled, chopped peaches and add them to a blender or food processor. Blend until smooth. (No blender? Mash them with a fork until smooth.) You need 1 full cup of pureed peach.
In a small saucepan, whisk together the sugar, cornstarch, Sure-Jell, and 1 cup of the peach puree and ½ cup of orange juice. Make sure to scrape the sides and bottom of the pan so everything mixes well.
Cook over medium heat, stirring constantly, until the mixture comes to a full boil. Boil for 2 minutes to fully cook the cornstarch (the glaze will start frothy, but as it boils, it will thicken into a nice, smooth glaze). Once thickened, remove from heat and stir in the butter until it’s completely melted and incorporated. Let the glaze cool to room temperature.
Prep the Rest of the Peaches: While the filling cools, slice the remaining peaches. To do this, first cut the peach in half along the natural seam, twist the halves to separate, and remove the pit. Cut each half into quarters, removing any red pit bits if necessary. Then, lay the peach on its flat side and slice across the short side into ½-inch thick slices.
Add the peach slices to a medium bowl and pour the remaining ½ cup orange juice over them to keep them from browning.
Once the glaze has cooled, drain the peaches, then put them back into bowl. Pour the glaze over the peaches. Then gently fold the glaze in until the peaches are fully coated. Scoop the mixture into the cooled pie crust, spreading it evenly. Refrigerate the pie for a few hours to chill before serving.
Serve: Serve the pie chilled, topped with whipped cream if desired!