Preheat the oven to 400°F (200°C).
Roll out the puff pastry on a lightly floured surface to a large rectangle, about 1/4-inch thick.
Place the Brie cheese in the center of the pastry rectangle, leaving a 1-inch border around the cheese.
Arrange the sliced apple on top of the Brie cheese, leaving a small border around the cheese.
Drizzle the honey over the apple slices.
Sprinkle the chopped walnuts over the apple slices.
Fold the puff pastry over the cheese, pressing the edges to seal.
Brush the pastry with the olive oil and sprinkle with salt and pepper.
Place the pastry on a baking sheet lined with parchment paper and bake for 20-25 minutes, or until the pastry is golden brown.
Remove from the oven and let cool for 5 minutes before serving.