Preheat your oven to 375°F. Set the brie wheel on a cutting board and use a paring knife to score the top in a crosshatch pattern, about halfway into the cheese. This helps the inside melt evenly and gives the berries somewhere to nestle in.
In a small saucepan over medium heat, combine the balsamic vinegar, honey, and blueberries. Let it simmer for 4–5 minutes until the berries soften and the liquid thickens slightly into a syrupy consistency. Stir occasionally so nothing sticks or burns.
Place the scored brie into your oven-safe skillet or dish. Spoon most of the blueberry balsamic mixture directly over the top, letting some drip into the scored lines. Sprinkle the fresh thyme and a pinch of flaky salt over everything.
Slide the dish onto the top rack and bake for 10–12 minutes, or until the brie looks soft, puffed, and slightly melted around the edges. You want it warm enough to ooze but still holding its shape when you pull it out.
Let the brie sit for 2–3 minutes after baking so it firms up just enough to slice or scoop without collapsing completely. Top with the remaining blueberry balsamic syrup, then serve immediately with crackers or bread.