1. Let lamb stand at room temperature 1 hour. Roll up lamb jelly-roll fashion; secure at 1-inch intervals with twine. Heat a large skillet over medium-high heat. Add oil to pan. Add lamb; cook 6 minutes, browning on all sides.
2. Combine ketchup and next 5 ingredients (through garlic) in a large bowl. Coat lamb evenly with ketchup mixture. Place lamb on the rack of a roasting pan coated with cooking spray; place rack in pan.
3. Preheat oven to 200°.
4. Bake lamb at 200° for 2 hours or until a thermometer registers 135° or until desired degree of doneness. Let stand 20 minutes before slicing.