Preheat the oven to 220°C. Brush the sides and bottom of a 23 cm pie plate with 1 teaspoon of the oil. Cover the bottom of the plate with an overlapping layer of potatoes, using a quarter of the total. Sprinkle with 1 teaspoon of the oil, 1/4 teaspoon of the pepper and a pinch of salt, 3 teaspoons of the Parmesan, one third of the spring onions and one third of the rosemary.
Repeat for 2 more layers. Top with a final layer of potatoes and the remaining oil and Parmesan. Place an empty pie plate or round baking dish on top of the potatoes and bake in the lower third of the oven for 50 minutes or until the potatoes are crusty on the bottom (lift gently with a spatula to check) and the torte is tender throughout.
Cool in the pan for 5 minutes before loosening the bottom and sides with a small spatula and inverting onto a platter.
Did you know?
*Potatoes are the number-one source of vitamin C, simply because they are the most consumed vegetable. *Plain potatoes are virtually fat-free, but 50g commercial potato chips contain about 12 grams of fat.