Altered ingredient amounts.
I'm giving this 5 stars on ease! The flavour is also very good. I doubled the garlic, used finely crush dried rosemary and sprinkled with some garlic salt after pouring on the tomato sauce. I suggest you keep a thermumeter in the meat and keep an eye on it. Everyone's oven is a little different. 4 hours would have been way past well done for my roast. This is a fabulous roast for Sunday supper! I'll do it again and again..rave reviews from the family. Garlic, Italian herbs, cayenne, salt and olive oil on baby red potatoes is a great compliment..put into oven last hour of lamb roast. EASY and elegant