Preheat your oven to 400°F (200°C).

In a mixing bowl, blend together softened cream cheese, shredded cheeses, and chopped herbs. Add garlic powder, salt, and pepper to taste.

On a lightly floured surface, roll out the chilled puff pastry to about 1/8-inch thick. Cut into 3-inch squares.

Place a tablespoon of cheese mixture in the center of each square. Fold corners to form a triangle, sealing the filling inside.

Press down on the edges with a fork to seal. Arrange the pastries on a parchment-lined baking sheet.

Beat an egg and brush the tops of the pastries for a golden finish.

Bake for 15-20 minutes until puffed and golden brown.

Cool slightly on a wire rack before serving warm.