Remove a ring of peel from around the circumference of each potato. Soak the potatoes in cold water to cover to prevent discoloring until you are ready to use them.
Heat the oil and butter in a sauté pan, add the rosemary and garlic, and sauté over low heat for 5 to 6 minutes, until the herbs have perfumed the oil, but have not browned.
Remove the herbs from the flavored oil and add the potatoes to the skillet. Sauté the potatoes over medium heat until golden, about 10 minutes.
Place the potatoes in a roasting pan, sprinkle them with salt and pepper, and bake them in a 375°oven until tender, about 40 to 50 minutes. Sprinkle them with the chopped parsley just before serving.