Directions

1. Preheat oven to 450 degrees F.
2. In a food processor, combine rosemary leaves, garlic, oil, vinegar, salt, and pepper and pulse to make a coarse, wet paste, scraping down the bowl as necessary. Spread 3/4 of paste on all sides of roast. Place roast, fat side up, in shallow roasting pan large enough to hold roast with 3 inches room around all sides. Roast 15 minutes.
3. Meanwhile, in a large bowl, combine potatoes and remaining paste.
4. Reduce oven to 350 degrees F. Add potato mixture to pan, arranging potatoes around roast. Continue roasting 40-45 minutes, tossing potatoes halfway through, or until internal temperature of roast reaches 145 degrees F and potatoes are tender. (If roast is done before potatoes, transfer it to a cutting board and return roasting pan with potatoes to oven.)
5. Remove roast from oven and let rest 10 minutes. Slice roast and arrange on platter. Surround with potatoes and serve.