Line a large baking sheet with parchment paper and preheat the oven to 350° Fahrenheit.
Roll the pie crust out on a flat clean surface and use a cookie cutter to cut circles out of 2 of the pie crust rolls.
Place the cut-out cookies on the baking sheet. Add 1-2 tablespoons of the blueberry pie filling to the middle of each cookie. Don't go all the way to the edge, leave a bit of pie crust edge around the blueberry filling. Sprinkle a little bit of lemon zest on top of the blueberry filling for each cookie.
Unroll the last two pie crusts and use a pizza cutter or knife to cut the crusts into thin 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 each cookie, pressing the edges down on the egg washed sides of the bottom crust. Do this step carefully so the strips don’t break.
Once you have all the strips placed correctly use the cookie cutter and place it over the cookies so the edges come clean from the lattice.
Brush the beaten egg over the top of each cookie. You just want to brush the pie crust strips and not the blueberry, 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.
Notes
Store in an airtight container in the fridge for 3-4 days.
The sanding sugar is just for decoration, you can skip it if you’d like. Or, use granulated sugar if you don't have sanding sugar.
Let the pie crust sit out for a few minutes before unrolling it. This prevents it from ripping.
Don’t let the pie crust sit out for too long or it will be too dry and hard to make the lattice with the strips.
If you don't have a round cookie cutter, use a cup instead.