150ml milk with (for dish size in photo)
1 tablespoon of plain flour
Salt and black pepper
A few knobs of butter
Peel and slice the potatoes thinly (about 3mm). Do the same with the onions and separate the rings.
In an open oven dish, layer the ingredients, potato, onion, grated cheese. Season each layer as you go. Use loads of black pepper – it’s a spice and not just seasoning in this dish. Do three layers, but on the top layer use only potato to form a topping.
Mix the flour into the milk (double quantities if using a large roasting dish) and pour over the other ingredients. Dob the knobs of butter over the top.
Place in an oven on 130C for about 4 hours. (If you’re in a rush, you can cook for 2 hours on 180C, with a foil cover for the first hour). When it’s crisp on top, it’s done.
Serve with almost anything. Good with a roast dinner. Great on its own.