Preheat oven to 475°F. In a medium bowl, combine potatoes, olive oil, rosemary, salt, and pepper, stirring to ensure that potatoes are evenly coated and seasonings are evenly distributed.
Place potatoes in the oven and roast for 10 minutes. Stir potatoes and continue roasting for about 8-12 more minutes (I usually find 10 is a good amount for 1" potatoes).