Ingredients

Makes 6 generous servings

　　

For lamb

1 1/2 cups plain whole-milk yogurt

　　7 garlic cloves, thinly sliced

　　2 1/2 tablespoons coarsely chopped fresh rosemary

　　1/2 teaspoon coarsely ground black pepper

　　1 (5 1/2-lb) piece boneless butterflied leg of lamb

　　1 1/2 tablespoons kosher salt

　　

For rosemary salt

1 teaspoon finely chopped fresh rosemary

　　1 tablespoon Maldon sea salt or other flaky sea salt

　　

Special Equipment

8 to 10 (12-inch) wooden or metal skewers; an instant-read thermometer

　　

Marinate lamb:

Step 1

Stir together yogurt, garlic, rosemary, and pepper in a 13- by 9-inch glass baking dish or 2-gallon sealable plastic bag. Add lamb, turning to coat completely, and marinate, covered and chilled, turning over once or twice, 5 hours.

　　

Step 2

Bring lamb to room temperature, about 1 hour.

　　

Step 3

Remove lamb from marinade, discarding marinade, and put on a work surface. Run skewers horizontally through meat, about 1 1/2 inches apart, first lengthwise (4 or 5 skewers), then crosswise (4 or 5 more) to form a grid. (Skewering makes meat easier to move and turn over.) Sprinkle with kosher salt.

　　

Step 4

Prepare grill for cooking. If using a charcoal grill, open vents on bottom of grill, then light charcoal. Charcoal fire is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds. If using a gas grill, preheat burners on high, covered, 10 minutes, then reduce to moderate.

　　

Step 5

Grill lamb, covered only if using a gas grill, on lightly oiled grill rack, turning occasionally, until thermometer inserted diagonally into thickest part of meat registers 125°F for medium-rare (thinner parts will register higher), 25 to 30 minutes if using charcoal or 20 to 25 minutes if using gas. Transfer lamb to a cutting board and let stand 10 minutes before thinly slicing.

　　

Make rosemary salt:

Step 6

Stir together rosemary and sea salt and serve with lamb.

　　Cooks' note:

　　If you aren't able to grill outdoors, you can cook lamb in a well-seasoned double-burner grill pan. Omit skewering and cut lamb into 3 or 4 pieces to fit in pan, then grill over moderately high heat, turning over once, 20 to 25 minutes.