A match made in heaven! If duck fat is unavailable use the same amount of melted butter instead.
1 kilogram medium Agria potatoes, peeled
2 tablespoons duck fat
1 red onion, very thinly sliced
2 tablespoons thyme leaves plus extra sprigs to garnish
½ cup freshly grated Parmesan
sea salt and freshly
Preheat the oven to 180°C.
Slice the potatoes very thinly. A mandolin is perfect for this.
Arrange one third of the potatoes in slightly overlapping circles on a lined baking tray. Drizzle with 2 teaspoons of duck fat then season generously. If the duck fat has solidified, warm gently to melt. Top with a third of the onion, thyme and Parmesan. Repeat to make two more layers, seasoning each with salt and pepper.
Cover loosely with a piece of foil and bake for 40 minutes. Uncover and continue to cook until the top is golden and the potatoes are tender when pierced with a knife, about 15–20 minutes.