| 1 | Boil the potatoes in their jackets until just tender. |
| 2 | Cool and store in the fridge to firm up for at least one day, prefer- ably two. |
| 3 | When ready to use, grate potato coarsely, finely chop the onion, mix together and season to taste. |
| 4 | (ruth says you can also add chopped bacon, to make speck rosti, though this is usually a breakfast dish). |
| 5 | heat the margarine in a frying pan and add potato mixture. |
| 6 | Do not press it down; keep it loose and light. |
| 7 | Cook it for 10-15 minutes on medium heat, turning it in sections a couple of times. |
| 8 | Towards the end, leave it to form a golden brown crust on the bottom. |
| 9 | Turnout, crust upwards, onto a platter and serve. |
