In a small bowl whisk together 2 tablespoons water with the cornstarch. In a small pot over medium heat reserved peach juice, cornstarch mixture, brown sugar and salt. Once the sauce thickens, about 5 minutes, stir in the chopped peaches.
In a chilled mixing bowl whip heavy cream with confectioners' sugar until soft peaks form. Use 1 cup for mug pies, and reserve the rest for the Caramel Cocktail recipe.
Begin assembling peach pies by in clear glass mugs. Place a layer of graham crackers at the bottom, then a big spoonful of the peach pie filling. Sprinkle with another layer of graham crackers. Top with a scoop of vanilla ice cream, then another layer of graham crackers followed by a dollop of whipped cream.