Step 1 of 4

Before you start, put your oven on its lowest setting, ready to keep things warm. Peel the potatoes, grate 2 of them, then set aside. Cut the other 2 into large chunks, then boil for 10-15 mins or until tender. Meanwhile, squeeze as much of the liquid from the grated potatoes as you can using a clean tea towel. Mash the boiled potatoes, then mix with the grated potato, spring onions and flour.