onion, peel, basil, and garlic in a small bowl. Whisk in 2/3 of oil. Rub
into pork. Wrap in foil and refrigerate overnight. Let pork stand at
room temperature 1 hour before roasting.
Preheat oven to 350
degrees F. Brush pork with remaining olive oil. Set on rack in shallow
pan. Roast until meat thermometer inserted in thickest part of meat
registers 170 degrees F, about 2 1/2 hours. Set meat aside.
Degrease pan juices. Blend Sherry into pan juices. Cover and cook over
low heat 2 minutes. Pour into sauceboat.
Transfer pork to
platter. Garnish with fresh parsley and lemon slices. Serve sauce