900g potatoes, two or three onions, 125g cheese

1. Heat 15g butter and the oil in a heavy-based frying pan or shallow casserole, about 21cm base diameter. Add a third of the potatoes, peeled and thinly sliced, to the pan then half the onions, thinly sliced, and about 50g cheese, seasoning as you go. Repeat layers of potatoes, onions and cheese, then finish with a top layer of potatoes and the rest of the cheese. Dot the last of the butter on top.
2. Crumple up a sheet of baking paper and lay it on top, tucking the edges inside the pan. Top with a tight-fitting lid (or use a heavy baking tray if you don’t have a lid). Cook on the hob over a low heat for about 40 minutes or until the veg are soft – pierce with a knife to check. Give the pan a shake occasionally, to make sure that the potatoes aren’t sticking.
3. When tender, turn up the heat under the pan to let the base crisp up for five minutes.
4. Then put the pan under the grill to brown the top. Let it settle for a few minutes before cutting into wedges. Serve as a side for sausages or chops, on its own with green veg or salad, or topped with a fried egg or bacon for brunch.

Learned at Naomi Cunningham’s house in Sussex. This is from the BBC Good Food website.