Make the dough: In a food processor, combine flour, salt, and sugar. Add the cold butter and pulse until the mixture resembles coarse crumbs. Gradually add ice water, 1 tablespoon at a time, and pulse until the dough comes together.

Chill the dough: Turn the dough out onto a lightly floured surface, shape it into a disk, and wrap it in plastic wrap. Chill in the refrigerator for at least 30 minutes.

Prepare the filling: In a medium bowl, combine the chopped hearts of palm, cream cheese, mozzarella, Parmesan, parsley, garlic powder, onion powder, salt, and pepper. Mix until smooth and well-combined.

Roll out the dough: Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper. Roll out the chilled dough on a floured surface to about ¼-inch thickness. Use a round cutter (about 3-4 inches in diameter) to cut circles of dough.

Assemble the hand pies: Spoon about 1-2 tablespoons of the hearts of palm filling onto the center of each dough circle. Fold the dough over the filling to form a half-moon shape. Press the edges together to seal, and crimp with a fork.

Bake: Brush the tops of the hand pies with the beaten egg for a golden finish. Place them on the prepared baking sheet and bake for 20-25 minutes, or until golden brown.

Serve: Let the hand pies cool slightly before serving. Garnish with fresh herbs, if desired, and enjoy!