Preheat your oven to 400°F (200°C).

In a mixing bowl, combine softened cream cheese, shredded cheeses, chopped herbs, garlic powder, and a pinch of salt and pepper. Blend until smooth.

Roll out the chilled puff pastry on a floured surface to about 1/8 inch thick. Cut into 3-inch squares.

Place a tablespoon of cheese filling in the center of each pastry square.

Fold corners together to form a triangle, pinching the edges to seal. Crimp with a fork for security.

Arrange the pastries on a parchment-lined baking sheet. Brush tops with beaten egg.

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

Cool on the baking sheet for a few minutes before serving.