1. Peel the potatoes and cut into 1/2-inch cubes. (If cutting in advance, hold in a bowl of cold water to prevent discoloration.)
2. Bring a large pot of water to a boil. Add the potatoes and return to a boil. Cook for 5 minutes. Drain and pat the potatoes dry with paper towels.
3. In a large non-stick skillet, heat the oil over high heat. Add the potatoes, in a single layer, and cook until golden brown on one side, about 10 minutes. Sprinkle with the rosemary, then turn and cook about 10 minutes longer, until evenly golden and crisp. Season with the salt and pepper to taste and serve.
Note: The potatoes may be prepared in advance and reheated uncovered in a hot oven on a baking sheet.
