1 boneless butterflied leg of lamb (4 to 5 pounds), trimmed
3 garlic cloves, slivered
3 tablespoons minced fresh rosemary
In a small skillet, saute minced garlic in oil for 2-3 minutes. Remove from the heat; stir in the spinach, cheese, 1/2 teaspoon salt and 1/8 teaspoon pepper.
Untie lamb and open so it lies flat; flatten to 3/4-in. thickness. Spread spinach mixture over meat to within 1 in. of edges. Starting with a short side, roll up lamb and tuck ends in; tie with kitchen string at 2-in. intervals. With a sharp knife, make slits on the outside of meat; insert garlic slivers. Sprinkle with rosemary and remaining salt and pepper.
Place seam side down on a rack in a shallow roasting pan. Cover and bake at 425° for 1 hour. Uncover; bake 15-30 minutes longer or until browned and a thermometer reads 160°, basting occasionally with pan juices. Let stand for 10-15 minutes before slicing.