First prepare the potato salad, as it needs to infuse for some time. For this purpose, boil the Kipfler potatoes until soft, peel them and cut them into slices as thick as the back of a knife. Mix the soup, oil, vinegar, mustard and salt, heat in a saucepan to just about boiling point and drizzle the liquid all over the potatoes. Stir in finely chopped onion, mix well and let sit for a while, covered, at room temperature. In the meantime, prepare the fried chicken. Cut the gutted chicken into quarters into legs and breasts (with wings), either bread the neck, backbone and giblets separately or use them further for a chicken soup. Salt the chicken pieces and roll them one after the other in flour, beaten egg and breadcrumbs, then press the breadcrumbs well all around with a fork. Heat oil and clarified butter in skillet and add chicken pieces only when fat is hot enough for a drop of water to sizzle loudly in it. Fry chicken pieces until golden brown and crispy all around, about 15 to 20 minutes, keeping the heat so that the chicken does not brown too much nor does the breading sag. The fried chicken is done as soon as you can pierce the leg pieces at the joint without red juices oozing out. If the chicken livers are also breaded, do not add the same until about 4 to 5 minutes before the end of the baking time or they will become dry. Lift the chicken out of the fat, drain thoroughly on paper towels, decorate with lemon slices and serve with the lukewarm potatoes.