Heat 2 cloves garlic in oil over low heat in a small skillet. Char bread slices under hot broiler to brown on both sides. Dab charred bread with garlic oil using a pastry brush. Place reserved oil in a small bowl with chopped olives. Place garlic cloves on a cutting board and pile together with capers, red pepper flakes and rosemary leaves. Finely chop garlic and herb mixture. Combine garlic-herb mixture with olives and oil in a small bowl. To assemble crostini, spread olive tapenade on toasts and enjoy!