Preheat your oven to 400°F (200°C).

In a medium skillet, melt a tablespoon of butter over medium heat. Add finely chopped mushrooms and minced garlic, sautéing for about 5-7 minutes or until soft. Season with salt, pepper, and chopped herbs, then set aside to cool.

On a lightly floured surface, roll out your puff pastry until 1/8-inch thick. Cut into squares, roughly 4x4 inches, keeping it cool.

Place a tablespoon of cooled mushroom filling in the center of each pastry square, leaving room around the edges.

Fold the pastry over the filling to create a triangle or roll it into a pinwheel shape. Seal securely by crimping the edges.

Beat an egg in a small bowl and brush it over the tops of the pinwheels.

Arrange pinwheels on a parchment-lined baking sheet, and bake for 15-20 minutes until golden and flakey.

After baking, let them cool for 5 minutes on a wire rack and serve warm.