It’s funny, when I lived in Switzerland I never made rösti from scratch. I guess it’s because it was so easy with the packaged stuff, just empty into a pan and fry up. And lots of flavours too!
When I left, my friends gave me a couple of Swiss cookbooks, one of which is Cooking in Switzerland by Marianne Kaltenbach. There on page 66 is a recipe for traditional rösti.
Parboil potatoes until partially tender, then cool and leave overnight
Peel and grate coarsely
Heat a knob of butter in a heavy frying pan and add the potatoes
Season with salt & pepper
Squash with a wooden spoon then sprinkle about 1 tbsp milk on top
Cover the pan and lower the heat
After about 20-25mins a crust would form and the rösti can move about in the pan
Carefully turn out onto a plate
What better to serve with traditional rösti than traditional brätwurst? Holy smokes, this all taste exactly of Switzerland.