TO ROAST THE GRAPES: Preheat oven to 425 degrees. In a small pot on medium-low heat, add the olive oil, honey, and the sprig of rosemary; cook slowly until fragrant about 5 minutes.
Toss the grape halves with the olive oil mixture, 1 teaspoon of dark balsamic vinegar; salt and pepper to taste.
Spread the grape mixture on a parchment-lined baking sheet and roast for about 25 minutes.
BRUSCHETTA: While the grapes roast, slice the bread on the diagonal and place under the broiler until crispy, about 2 minutes. Watch carefully! Remove from the oven and spread with the goat cheese. Top with the roasted grape mixture.