Slivered potatoes with white onion and Lancashire cheese

Method

1. Heat the oven to 160°C/140°C fan/gas 3. Peel the potatoes and slice thinly using a sharp knife/mandoline. Put in a bowl, cover with cold water and leave for 5 minutes (to get rid of the starch; see Make Ahead). Slice the onions in half through the root, then into thin half-moons. Drain the potatoes and dry on kitchen paper.
2. Rub a garlic half over the base of the baking dish, then grease with butter. Melt the 60g butter in a pan. Crush the remaining garlic, add it to the pan and cook for a minute. Add the cream and stock to warm up.
3. Layer half the onions, followed by half the potatoes over the base of the baking dish and season well with salt and pepper. Grate a quarter of the Lancashire cheese over the potatoes. Layer the rest of the onions over and the remaining potatoes and season again. Pour over the hot cream/stock, season again and grate over the rest of the cheese.
4. Bake for 1 hour 20 minutes or until the top is golden and bubbling and the potatoes are tender to the point of a knife. Cover and set aside until ready to serve with the ham.