Instead of roasties, try gratin potatoes with your roast lamb. Thinly slice potatoes and onions. Simmer a mug of milk and a mug of cream with some crushed garlic and thyme, then strain. Layer half the potatoes and onions in a dish, pour in half the cream, then top with more potatoes, onions and the rest of the cream. Grate over a little cheese. Bake for 11/2 hrs in a medium oven till golden and a skewer inserted into the potatoes goes through easily.