On the day before, make small incisions in leg of lamb. Insert the slices of garlic in each incision. Keep 1/4 of the garlic for inside of lamb. Rub olive oil inside lamb and insert the rest of the garlic and rosemary in the center. Pepper, then roll and tie the lamb with cotton twine. Rub olive oil and pepper outside of lamb. Put on a tray, cover and refrigerate. To cook, preheat oven to 350 degrees F. In large skillet, add leg of lamb and brown all sides. Place on rack in roasting pan. Bake for 1 hour 15 minutes (depending on size). Turn lamb a couple of times. When done, the internal temperature should be 140 degrees F. Remove from oven. Let rest 15 to 20 minutes before slicing.
