Special equipment: a 3-inch round cutter and 20 to 24 short lollipop sticks
In a food processor, pulse the berries a couple of times until they are in large chunks. Add to a medium saucepan with the sugar, salt and orange juice. Bring to a low simmer over medium heat and simmer gently until the berries have released their juices and the mixture has slightly reduced, about 20 minutes.
Mix the cornstarch with 2 tablespoons water in a small bowl to create a slurry and add it to the saucepan. Cook until the mixture is combined and reduced, about 5 minutes. Transfer the mixture to a bowl and place in the freezer for 20 to 30 minutes.
While the berry mixture is cooling, make the full box of pie dough according to the package instructions. Separate the dough into 2 or 3 balls and roll each out on a floured surface to 1/8 inch thick. Refrigerate for at least 5 minutes.
Preheat the oven to 450 degrees F. Line a baking sheet with parchment paper.
Cut out dough rounds with a 3-inch round cutter and fill one round with 2 to 3 teaspoons of the cooled berry filling. Brush the rim of the dough with the egg wash, top with another round and then seal with a fork all the way around. Repeat until all of the dough rounds have been used. Brush the top of the lollipies with the remaining egg wash and sprinkle with demerara sugar.
Bake on the prepared baking sheet until a dark golden brown, about 15 minutes. Let cool, then stick a lollipop stick in through one of the sides of each pie.