1 (14-ounce) box unroll-style refrigerated pie dough
Remove the pie crusts from the refrigerator and let the pouches stand at room temperature to soften up, 10 to 15 minutes.
Meanwhile, set your oven rack to the middle position and heat the oven to 425°F. Line a rimmed baking sheet with parchment paper.
1 cup (4 ounces) shredded cheddar cheese, ⅔ cup refrigerated spinach-artichoke dip
In a small bowl, use a spoon to stir together the shredded cheddar and artichoke dip until well combined.
Lay out another sheet of parchment paper on the counter. Gently unroll one of the softened pie crusts onto the parchment sheet. Use the spoon to spread the cheddar-artichoke filling evenly over the pie dough.
Unroll the second pie crust/pastry and place it on top of the filling to form a sandwich. Press the top crust down gently to stick everything together. Use a bat-shaped cookie cutter to cut out shapes from the filled pastry and transfer them to the parchment-lined baking sheet. Keep the cutouts as close together as you can to get as many bats as possible; you'll get 8 to 10 depending on the size of your cutter. If the cutouts don’t transfer easily in the cookie cutter, use a small offset spatula to help move them to the baking sheet. For the cleanest edges of the bat shapes, transfer the baking sheet to the freezer for 15 minutes or the fridge for 30 minutes. If you don’t mind them being a little messy, keep going!
1 large egg, 1 teaspoon water, 1 to 2 tablespoons black sesame seeds or poppy seeds
In a second small bowl, combine the egg and water. Use a fork or small whisk to beat until well combined. Use a pastry brush to lightly paint the tops of the bats with the beaten egg. Sprinkle each bat evenly with the black sesame seeds or poppy seeds, if you like.
Place the baking sheet in the preheated oven. Bake until the pastry is deep golden and the cheese is bubbly inside, 12 to 15 minutes. Some of the cheese may bubble out of the sides, and that's okay!
Use oven mitts to remove the baking sheet from the oven and place it on the stovetop or a cooling rack. Let cool for 5 minutes, then use a spatula to transfer each bat to a serving plate or a platter and serve warm.