Historically, rösti was a Swiss farmer's breakfast from the canton of
Bern, a bit similar to
hash browns. Nowadays it is a
Swiss national specialty. Rösti is pronounced
røʃti.
Rösti is mainly eaten in the German-speaking part of Switzerland. The term Röstigraben ("rösti dig") is used to indicate the difference in political and ideological views between the German speaking and non-German speaking Swiss.
There is much discussion on what 'true' rösti consists of. However, the basis is always grated potato, fried into a pancake-like shape. The biggest point of conflict is whether the potatoes should be cooked before grating or not. In Bern, cooked potatoes are used, in Zürich uncooked. Apart from regional preferences, a way to solve the cooked/uncooked dilemma is to consider the way the rösti will be eaten. If it is to be eaten as a side dish, together with a sauce, the rösti should be able to absorb the sauce and should be made with cooked potatoes. If the rösti is eaten as a main dish, it can be made with raw potatoes.
Apart from potatoes, many ingredients can be added to rösti. Each Swiss canton and region has its own special variety of rösti:
Even apart from these regional varieties, rösti is a very versatile dish. You can substitute part of the potato with
carrot or with
celeriac. You can add mushrooms or melt
raclette cheese on top. You can make it into one big pan-filling rösti or you can make small cookie-sized röstis. The possibilities are (almost) endless.
Obviously, the best thing to do would be to go to Switzerland and have someone make the authentic rösti for you. But for those people for whom this is not a possibility, here is a recipe for the most basic kind of rösti. For four people, peel and grate 1 kilo of potatoes. Melt 3-4 table spoons of oil or butter in a frying pan or skillet. Add the potatoes and 1 tablespoon of salt. Mix everything well. Cover the pan and fry for 20 to 30 minutes at medium heat. During this time, mix the rösti every once in a while. Then turn up the heat and fry for another 20 minutes, mixing now and then. When the rösti is almost done, form it into a pancake shape by pressing it into the pan. Serve hot.
Sources: Wikipedia and several recipe sites
Thanks to Siobhan for comments and corrections!