Preheat the oven to 400 degrees F.
Cut the potatoes in half or quarters and place in a bowl with the olive oil, salt, pepper, garlic and rosemary; toss until the potatoes are well coated. Dump the potatoes on a baking sheet and spread out into 1 layer; roast in the oven for at least 1 hour, or until browned and crisp. Flip twice with a spatula during cooking to ensure even browning.
Remove the potatoes from the oven, season to taste, and serve.
