Place one half of the dough in a floured work surface and roll into a rectangle that is 9x12". Using a pizza cutter, cut the dough in 3 inch intervals so you have 4 individual strips of dough.
Beat the egg and milk together. Brush over the strips of dough. Place one tablespoon of filling on each strip towards one end, but leaving at least ¼ inch border. Fold the top over so the two edges meet and seal them with your fingers. Once sealed, take a fork and gently press the tines along all 4 edges. You can take a knife and trim the edges to make them straight.
Repeat with the other half of the dough.
Place the pop tarts on a parchment lined baking tray and prick the top of each pop tart with a fork. Refrigerate uncovered for at least 30 minutes.
Preheat the oven to 350°F/175°C.
Remove the tarts from the fridge and brush them with the remaining egg wash. Bake for 30-35 minutes, until a light golden brown. Allow them to cool completely.