Preheat oven to 350℉. Coat 4 muffin tin slots with nonstick cooking spray. Set aside.
In a small bowl, beat the egg with a little splash of milk to make an egg wash.
In a small bowl, mix the peaches, peach jam, brown sugar, cinnamon, and salt.
With your first crust, cut out four 5" rounds and gently press into each muffin cup, leaving a slight overhang. Evenly distribute the peach mixture into each cup.
With the second crust, cut out four 3" rounds and place on top of each muffin cup, crimping the bottom and top crusts together.
Pierce the top crusts with a knife and brush with the egg wash. Sprinkle with a little granulated sugar.
Bake until golden and peaches are tender, about 35 minutes.
Let cool for a few minutes and enjoy with vanilla ice cream!