Preheat the oven to 350°F (175°C).
Place the Brie wheel in a small oven-safe baking dish or on a parchment-lined baking tray.
Add the blueberries, honey, lemon zest, lemon juice, and cinnamon to a small saucepan. Cook over medium heat for 3–5 minutes, stirring gently, until the blueberries begin to soften and release their juices.
Spoon the warm blueberry mixture over the Brie. Sprinkle the chopped pecans or walnuts and fresh thyme on top.
Drizzle the Brie with a little extra honey.
Bake for 12–15 minutes, or until the Brie is soft and creamy in the center. Avoid overbaking, as the cheese may spread too much.
Carefully remove the baked Brie from the oven and let it rest for 2–3 minutes.
Serve warm with crackers, crostini, or toasted baguette slices.