Peel the potatoes and slice thinly. Rinse the potatoes with warm water and dry thoroughly with paper towels. Melt the butter in 2 large frying pans and cook the potatoes over a medium-high heat, turning frequently, until they are well browned. Sprinkle with salt and pepper. Reduce the heat to low, cover and cook for 15 minutes, until the potatoes are soft. In a small bowl stir together the crÅme fraöche, mustard, and herbs. Combine all the potatoes together in one frying pan and pour over the cream mixture. Stir to coat the potatoes. Simmer gently, stirring occasionally, about 5 minutes.
