Preheat oven to 425°. Combine 1 cup halved cherry tomatoes, 1 tablespoon olive oil, 1 sliced garlic clove, 1/4 teaspoon salt, 1/2 teaspoon black pepper, and 1/4 cup fresh basil leaves; roast in middle of oven until tomatoes wilt and are golden (about 20 minutes). Remove from oven; drizzle with 2 teaspoons balsamic vinegar. Roast an additional 10 minutes. Spread 1/4 cup packaged herbed goat cheese evenly onto 12 toasted crostini; top with tomato mixture.