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

Toss the thinly sliced pear with the lemon juice to prevent browning. Set aside.

In a small bowl, combine the cranberry sauce, 1 tablespoon of honey, thyme leaves, and black pepper. Stir until evenly mixed.

Unfold one sheet of puff pastry onto the prepared baking sheet. Lightly mark a Christmas tree outline, including a trunk, and cut around it. Spread the cranberry mixture in a thin layer over the tree, leaving a small border around the edges.

Arrange the Brie slices, pear slices, and dried cranberries evenly over the cranberry mixture. Keep the filling away from the edges so the pastry can seal properly.

Cut the second sheet of puff pastry into a matching tree shape. Place it over the filling and gently press around the edges to seal. Trim any uneven edges and save scraps for decorative stars or other shapes, if desired.

Using a sharp knife, cut horizontal strips from both sides toward the center, leaving the middle trunk intact. Twist each strip gently two or three times to create pull-apart branches. Avoid twisting too tightly, as the filling may escape.

Whisk the egg with the water. Brush the pastry evenly with the egg wash for a glossy, golden finish.

Bake for 22–28 minutes, or until the pastry is puffed and deep golden brown. If the pastry browns too quickly, loosely cover it with foil for the final few minutes. Let it rest for 5–10 minutes before adding the drizzle.

While the pastry bakes, mix the 2 tablespoons of honey, chopped walnuts, and balsamic vinegar in a small bowl.

Drizzle the walnut-honey mixture over the warm pastry tree. Garnish with extra walnuts, dried cranberries, fresh thyme, and flaky sea salt. Serve warm so the Brie stays soft and creamy.