Historic village bakery classic: thinly sliced potatoes and sweet onions layered in a baking dish, soaked in rich savory lamb or vegetable stock, and baked until tender with a crispy, golden top.
Melt half the butter with olive oil in a pan. Sauté sliced onions over medium heat for 12 minutes until soft, sweet, and golden.
In a buttered baking dish, layer sliced potatoes and caramelized onions, seasoning each layer with thyme leaves, salt, and pepper. Finish with a neat overlapping layer of potato slices on top.
Pour hot savory stock over the potatoes until it reaches just below the top layer.
Dot top with remaining butter. Bake at 190°C for 50-60 minutes until potatoes have absorbed the broth and the top is crisp, roasted, and deep golden.