Preheat oven to 375 degrees. Cut slices down the length of bread loaf at 1 inch intervals, without cutting all the way through. Rub slices and top of loaf with cut sides of garlic halves. Mince garlic. Combine butter, garlic, parsley and Parmesan in a small bowl. Spread butter mixture between bread slices and on top of loaf. Wrap bread in foil, leaving top partially uncovered. Bake until heated through, about 15 minutes.