Leeks are cleaned, cut and stew in the butter and add a little water until soft. Apart Peel and boil the potatoes, grate, seasoned with salt, white pepper and mustard and mix with leeks. Add cream and olive oil optional. You can increase the amount of cream, if you want a juicy salad. The Brie cut into small cubes and spread over the potatoes, top Sprinkle parsley.