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

Roll out the thawed puff pastry on a floured surface until about 1/8 inch thick, then transfer to the baking sheet.

Cook diced pancetta in a skillet over medium heat until crispy, about 3-5 minutes. Drain on paper towels.

Fold the pastry edges inward to create a border, layer Brie, cranberry sauce, and pancetta in the center, and brush edges with egg wash.

Bake for 20-25 minutes until the pastry is golden brown and fillings are bubbly.

Let cool for about 5 minutes, garnish with thyme, slice, and serve warm.