1. Place a steel, cast iron or aluminum pan in a hot oven for a new minutes to heat it up. Add olive oil and return to the oven until the oil is hot, but not smoking.
2. Place the potatoes in the pan, and add the rosemary. Season with salt and pepper. Stir to coat the potatoes with the oil.
3. Cook for 10-15 minutes, until the potatoes are brown, and tender when pieced with a fork. You might need to turn the potatoes once, depending on where you oven is the hottest.