Preheat the oven to 375 F.

Place the lamb onto a roasting pan. Pour ¼ cup olive oil over the lamb and rub the olive oil onto all sides of the meat to coat. Sprinkle the lamb evenly with 4 ½  teaspoons salt and 3 teaspoons black pepper. 

Add the potatoes into the pan around the lamb. Pour ¼ cup olive oil, ½ teaspoon salt and ½ teaspoon pepper over the potatoes and toss to coat. Place the rosemary branches around the pan making sure some are making contact with the lamb and some are with the potatoes. Add the two garlic cloves to the potatoes. 

Transfer the baking pan into the oven and roast uncovered for 1 ½ hours until the lamb is cooked through and the potatoes are golden and tender. 

Serve hot. Micaela likes to serve the lamb whole at the table and to slice and serve at the table.