Preheat your oven to 400°F and line a baking sheet with parchment paper to prevent sticking.

Carefully unfold the thawed puff pastry sheets. Cut each sheet into thirds lengthwise, then cut each strip in half to create six rectangles per sheet. Place the rectangles on the prepared baking sheet, leaving some space between each so they bake evenly. Using the blunt side of a butter knife, gently score a border around each rectangle, about ¼ to ½ inch from the edges, this helps the filling stay in place while the edges puff up.

In a medium or large mixing bowl, combine the spinach (squeezed dry), chopped artichoke hearts, cream cheese, and shredded mozzarella. Stir until the mixture is evenly blended.

Spoon the spinach-artichoke mixture into the center of each rectangle, keeping it inside the scored border.

Crack an egg into a small bowl and whisk it until smooth. Using a pastry brush, lightly brush the egg wash along the edges of each pastry to give them a glossy, golden finish.

Place the baking sheet in the preheated oven and bake for 15-17 minutes, or until the puff pastry turns golden brown.

Remove from the oven and let the pastries cool slightly before serving. Enjoy them warm for the best flavor and texture!