Start by preheating your oven to 450°F so it's nice and hot by the time your crostini go in. While that's heating, slice your baguette into rounds about half an inch thick. Lay the slices flat on a parchment-lined baking sheet so they don't stick and bake evenly.
Place a slice of brie on top of each piece of bread, letting it sit right at the edges so it melts evenly. I don't worry too much about trimming the rind since it's completely edible and adds a nice earthy note. Just make sure every slice gets a good amount of cheese.
Scatter fresh thyme leaves over the cheese-topped bread before it goes into the oven. This step infuses the brie with flavor as it melts rather than just sitting on top. If you don't have fresh herbs on hand, a light pinch of dried herbs works fine too.
Slide the baking sheet into the oven and bake for about 5 minutes, watching closely the whole time. You're looking for the edges of the bread to turn golden brown and the brie to go soft and melty. Ovens vary, so check at the 4-minute mark to avoid overbaking.
Pull the crostini out of the oven and immediately drizzle honey over each piece while it's still warm. The heat helps the honey soak in slightly and coat the melted cheese beautifully. Serve right away for the best texture and flavor.