Step 1: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Step 2: On a lightly floured surface, unroll the thawed puff pastry sheet. If desired, use small Halloween-themed cookie cutters (like bats or ghosts) to make shapes from the pastry scraps for decoration.
Step 3: Place the wheel of Brie cheese in the center of the puff pastry. Top the Brie with 2-3 tablespoons of the seedless raspberry jam, spreading it evenly but leaving about an inch clear around the edges.
Step 4: Carefully fold the puff pastry over the Brie, gathering and pinching the edges to seal completely, forming a neat package. Trim any excess pastry. Place the sealed Brie package seam-side down on the prepared baking sheet.
Step 5: In a small bowl, whisk the egg with 1 tablespoon of water to create an egg wash. Brush the entire surface of the puff pastry with the egg wash. If you made pastry decorations, place them on top and brush with egg wash too.
Step 6: Bake for 20-25 minutes, or until the pastry is golden brown and puffed, and the cheese is melted and gooey inside.
Step 7: Carefully transfer the Bloody Baked Brie to a serving platter. If desired, drizzle a little extra raspberry jam artfully over the top to enhance the "bloody" effect.
Step 8: Serve immediately with an assortment of crackers, crusty bread, or fresh apple slices.