Preparation

• Heat the oven to 400°F. Put the potatoes in a large bowl and drizzle with 2 tablespoons of the oil. Season well with salt and pepper and toss. Spread the potatoes on a large baking sheet and roast until they’re slightly brown and easily pierced with a fork, 15 to 20 minutes.
• Meanwhile, heat the remaining 2 tablespoons oil in a large skillet over medium heat. Add the bacon and cook, stirring occasionally, until golden brown, about 10 minutes. Using a slotted spoon, transfer the bacon bits to a paper towel to drain.
• Add the onion to the pan, season with salt and pepper, and cook until the onion is softened, 3 to 4 minutes. Add the vinegar, mix well, and then add the cooked potatoes, apple, bacon, parsley, and rosemary. Gently fold everything together until evenly coated. Season with salt and pepper and serve immediately.