Ingredients

• 6 garlic cloves
• 9 flat anchovy fillets, drained and patted dry
• 1/4 cup olive oil
• 2 1/2 tablespoons chopped fresh rosemary
• 1 (6- to 7-lb) semiboneless leg of lamb (aitchbone removed), all but a thin layer of fat discarded and lamb tied
• 2 teaspoons salt
• 3/4 teaspoon black pepper
• a 17- by 11-inch roasting pan (or larger) with a rack; an instant-read thermometer

Instructions

1. Mince garlic and anchovies and mash to a paste with a large heavy knife, then stir together with oil and rosemary in a small bowl. Pat lamb dry and transfer, fat side up, to rack in pan. Make several small 1-inch-deep slits in lamb with a paring knife, then rub marinade over entire surface of lamb, pushing some marinade into slits. Marinate lamb, loosely covered, at room temperature 1 hour.
2. Put oven rack in middle position and preheat oven to 400°F.
3. Sprinkle lamb all over with salt and pepper, then roast until thermometer inserted into thickest part of lamb (almost to the bone but not touching it) registers 125°F for medium-rare, 1 1/2 to 1 3/4 hours (temperatures in thinner parts of leg may register up to 160°F). Let stand 30 minutes before slicing.