2 tbsp melted butter
salt and pepper
Preheat the oven to 180C. Brush the dish with melted butter. Peel the potatoes and slice them thinly on a mandolin. Do the same with the onion. Layer the potatoes overlapping slightly. Top with a scattering of onion and a sprinkle of salt and pepper and thyme. Repeat until all the potato has been used. Heat the stock and pour it over the potatoes and then brush the top layer with melted butter and bake for an hour.