Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a mixing bowl, combine coarsely chopped pistachios, honey, rosemary, sea salt, and black pepper. Mix until well combined.

Roll out the chilled puff pastry to 1/8 inch thickness and cut into 3x3 inch squares.

Place a piece of Brie cheese in the center of each pastry square. Top with pistachio mixture and fold over the pastry corners to seal.

Beat egg with water and brush the tops of the bites for a golden finish.

Bake for 15 to 20 minutes, or until puffed and golden brown. Watch closely to avoid burning.

Remove from the oven and garnish with cranberries or pomegranate seeds before serving warm.