Preheat the oven to 400 degrees. Place the grapes on a baking sheet then drizzle with olive oil and season with a bit of sea salt, to taste. Toss a sprig of thyme on top.
Place into the oven and roast for 15-20 minutes, or until tender and slightly wrinkled, remove from the oven and set aside.
While the grapes are roasting, place the baguette slices on another baking sheet. Place into the oven on another rack and bake, about 10 minutes or until golden brown and crisp, flipping halfway through baking.
Place the crostini on a serving tray then add a slice of brie to each piece. Top with a spoonful or two of grapes and drizzle with honey, if desired. Side Note: Taste the grapes first because you may not need any honey!