4 potatoes, preferably Yukon Gold or Russet
2 tablespoons olive oil
3 sprigs fresh rosemary, or 2 teaspoons dried
Salt and freshly ground pepper
Heat oven to 425 degrees. Cut potatoes lengthwise into thick slices, then into 1/2-inch-by-1/2-inch-thick strips. Place in a bowl of cold water until ready to use. Drain and dry well on paper towels.
Toss potatoes with oil and spread out on a dark roasting pan or baking sheet. Scatter rosemary over potatoes. Bake for 35 to 40 minutes, turning occasionally, until potatoes are brown and crisp on all sides.
Remove from oven, sprinkle with salt and pepper, and serve immediately.