Transfer the sliced potatoes to a large bowl and add the olive oil, minced rosemary, garlic, salt, and pepper.
Mix until thoroughly combined.
In 1-quart au gratin style oval casserole dish, layer and an the potatoes around and in the inside until all the potatoes have been used.
Season with salt and pepper, place on the rosemary sprig, and pour in the chicken stock just until it reaches the top layer of the potatoes.
Drizzle on the olive oil and bake at 375° for 50 to 60 minutes or until the potatoes are tender and the top slices are browned.
Notes
Make-Ahead: The roasted potatoes should be served as soon as they come out of the oven. If you’re running behind, cover the potatoes with foil and keep them in a 200ºF oven until it’s time to eat.How to Store: Keep the leftovers in the covered casserole dish or transfer them to an airtight container. They’ll stay fresh in the refrigerator for up to 4 days or in the freezer for up to 3 months. Thaw the potatoes in the fridge overnight before reheating.How to Reheat: Place your desired amount of potatoes in a baking dish and reheat in a 350ºF oven for 10 minutes or until warm. If needed, add another splash of broth to the dish to re-soften the potatoes.Patate al forno means roasted potatoes in English and is a classic Italian contorno (side dish).I like to make this recipe in a 1-quart au gratin-style oval casserole dish, but you can use any large oven-safe skillet or baking dish.Some Italians prefer to make patate in padella or potatoes in a skillet. I like the oven-roasted method over the stovetop because it’s more hands-off, and the potatoes become softer.Always peel the potatoes for easy slicing and the softest bites.Slice the potatoes with a mandolin for evenly sized and almost paper-thin rounds.Use enough chicken stock to reach the top layer of potatoes. This helps each layer of potatoes cook all the way through. Avoid submerging them in the stock or else you’ll miss out on the crispy golden top.If the potatoes' tops brown too quickly in the oven, you can cover them with a loose layer of foil.Let the roasted potatoes rest for at least 10 minutes before serving. This helps them firm up and gives them some time to cool.Feel free to serve the roasted potatoes with a sprinkle of cheese on top. Freshly grated parmesan, pecorino Romano, and mozzarella would work well.