Preheat your oven to 400°F (200°C). Roll out the thawed puff pastry on a lightly floured surface until it's about 1/8 inch thick, and cut into strips.

Place the brie cheese on a parchment-lined baking sheet and drape pastry strips over it, leaving gaps for an authentic mummy look.

In a bowl, whisk together the egg with water for the egg wash. Brush it generously over the pastry.

Bake in the preheated oven for 20-25 minutes until puffed and golden brown; keep an eye on it to ensure it doesn't burn.

Slice olives to prepare the eyes, and gently press them onto the cooled pastry.

Transfer to a serving platter, and serve with cranberry sauce or pumpkin spice dip.