Rosti Potato Cake

2 lbs yellow potatoes
2-4 tablespoons clarified butter or ghee
salt

1. Boil the potatoes in salted water just until cooked but not too soft. Let cool.
2. Grate the potatoes using the large holes in a box grater. Don’t worry about the skin. It will mostly slough off as you grate the potatoes and you can pick off the big pieces.
3. Heat 1-2 tablespoons clarified butter in a 10 inch heavy skillet or cast iron pan over medium heat. Swirl it around the pan and up the sides of the pan a bit. Add the potatoes evenly, sprinkle generously with salt, and press down and shape into a disc. Let it cook, undisturbed, for about 8 minutes or until nicely browned on the bottom.
4. Slide the cake onto a plate, cover with another plate and invert. Add more clarified butter to the pan and slide cake back in. Press down and cook another 8 minutes or until golden brown. Cut into wedges and serve with sour cream.