Boil potatoes, drain, rinse and peel. Dice the bacon and onion. Melt the bacon in a pan. Add the onion cubes and sauté in them until translucent. Add butter and melt. Stir in flour. Gradually stir in the milk and stock. Season to taste with salt and pepper. Slice the potatoes and add them to the sauce. Garnish with parsley leaves. Diced Kat ham tastes good with it.