Line a large baking sheet with parchment paper and preheat the oven to 350°.
Roll 2 of the pie pie crusts out on a flat clean surface and use a cookie cutter to cut circles out.
Add the cut out cookies to the baking sheet.
Add 1-2 tablespoons of the blueberry pie filling to the middle of each cookie.
Make sure to leave a tiny bit of pie crust around the blueberry filling.
Sprinkle a little bit of lemon zest on top of the blueberry filling on each cookie.
Unroll the last two pie crusts and use a pizza cutter or knife to make small strips.
In a small bowl add the egg and stir, brush the beaten egg around the edge of the cut cookies making sure there’s no blueberry filling on the edges.
Take the pie crust strips and make a lattice pattern on the cookie, pressing the edges down on the egg washed sides. Do this step carefully so the strips don’t break.
Once you have all the strips placed correctly use the same cookie cutter and place over the cookies so the edges come clean from the lattice.
Brush the beaten egg over top of each cookie once again carefully (try not to let the blueberry filling brush onto the strips) and then sprinkle with the sanding sugar.
Bake in the oven for 20-25 minutes or until the tops are golden brown.
Let cool completely and then serve and enjoy!