Grate the Potatoes (I like the skin left on but you can remove it if you wish), using the large holes of a hand grater or a food processor.
Slice the leeks by cutting them in half lengthwise and than into half moons.
Put the potatoes and leeks in a large bowl, add the salt and pepper, and toss to coat thoroughly.
Let the potatoes rest for at least 5 minutes, and then, working with a ?stful at a time, squeeze as much liquid as possible out of them and transfer to a second bowl. (The potatoes will start to discolor, but that won’t really e?ect the ?nal results.).
I make individual rosti by using small 4 inch pans but you can them using any size pan you have and cut them to individual servings.
Heat a heavy-based pan over medium-high heat. Add a bit of the melted butter.
When the temperature is right, take a ?stful of potatoes & leeks, wring it out once more, and let it fall loosely from your ?ngers into the center of the pan.
Working quickly, repeat until you’ve got enough potatoes in the pan to cover the bottom.
With a fork, gently spread out the shreds of potato to make a layer about 1/2 inch thick.
Cook until the underside is a deep golden brown and the potatoes on the top are starting to look translucent.
Flip the rösti over and slide the inverted rösti back into the pan and continue cooking until the new bottom is browned and the potatoes feel really tender in the middle. Another 6-8 minutes.