1TBSP heavy cream (or more as needed for desired consistency)
Preheat oven to 400 degrees Fahrenheit. Line a baking sheet with parchment paper and set aside.
In a small bowl, mix ½ cup jam with cornstarch. Crack egg into a second small bowl and whisk.
Flour a large work surface and lay both pie crusts out on it. Roll the circles to 11 inches across. Use a knife or pizza cutter to cut the edges off, and 1 inch off all sides, to create two 9-inch squares. Then cut each square into three 3-inch stripes, or six total.
Spoon 1-2 tablespoons of jam on one end of each strip. Brush a rectangle of egg around the jam, to glue the sides together. Fold the dry end over the end with jam.
Use a fork to crimp the edges together on all sides. Repeat with remaining pie crust strips.
Move pop-tarts to the prepared baking sheet. Bake for 15-18 minutes, until golden. Cool.
After the pop tarts have cooled for several minutes, whisk powdered sugar, 1 tablespoon jam, and 1-2 tablespoons cream together to create an icing glaze. Spoon over the top of each pop tart and immediately sprinkle with sugar sprinkles. Let icing dry and serve warm.