Preheat oven to 400°F. Wash and dry potatoes. In a mixing bowl, toss whole potatoes and garlic cloves with oil, rosemary, salt, and pepper. Spray a baking dish with nonstick spray. Arrange potato mixture in baking dish in a single layer. Cover with lid or aluminum foil. Bake for 25 minutes. Remove lid or foil. Turn potatoes and bake uncovered for another 25 minutes or until potatoes are soft and slightly browned. Pour into a serving bowl, mix with butter and serve. Yield: 4 servings.