M&S Collection Salt Dry Aged Lamb with Mint Butter Chosen for flavour and succulence, this British boneless lamb leg has been salt aged for 8 days, been expertly butchered and finished with a meaty lamb stock and mint butter; creating a roasting joint which delivers ultimate convenience as the joint is easy to cook and carve. Oven cooks in 55 to 60 minutes. Welcome to Collection from M&S, where exceptional quality and intricate attention to detail makes for something truly special. 100% of M&S Select Farms products meet our high quality and environmental protection standards. We know and trust all our Select Farmers, so you can trust M&S for your fresh food.