Preheat oven to 450°. Melt butter in a microwave. Stir in Italian seasonings, garlic powder, salt & pepper. Rub all over the lamb. Let it sit in room temperature for 30 minutes to an hour.
Place in a roasting pan and roast for 1 1/4 to 1 1/2 hours, or until the thermometer reads 135 for rare, 145 for medium. Remove from the oven. Cover tightly with foil to rest for 15-20 minutes.