Cook potatoes: Wash the potatoes. Leave the small potatoes whole and cut the larger ones so that all potato pieces have a similar size, about 3-4 cm/ 1.2 – 1.6 inches. Place in a pot with salted water. Bring to a boil and let boil for 4 minutes. Drain well. Place on a large kitchen cloth and pat dry (Note 2).You can proceed with the recipe for confit potatoes now or refrigerate the parboiled potatoes until the next day.
Heat fat: In the meantime, preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit. Place the goose fat in a roasting tin large enough to hold all the potatoes in a single layer. Place in the oven and let the fat melt, and get hot for about 10 minutes.
Prepare for roasting: Remove from the oven and carefully place the dried potatoes into the roasting pan. Turn them into the fat to coat all over.
Season: Add the peeled garlic cloves and the rosemary sprigs. Sprinkle with a bit of salt and pepper.
Roast for about 30-40 minutes or until the potatoes are golden brown and crispy on the outside and very tender on the inside. Shake the pan a couple of times in between to make sure that the potatoes are browning on all sides.
Serve immediately sprinkled with some more salt and pepper.
Nutrition: You will need 150 g/ 5.3 oz goose fat to make the potato confit. However, most of it will be left in the pan. So, I only considered 2 tablespoons of goose fat in the nutrition calculation. It is not entirely accurate, I suppose, but it is the best I can offer. Parboiling the potatoes for 4 minutes reduces the roasting time considerably and allows you to start preparing the dish in advance.