Peel and cut the potatoes and cook them in salted water until they are firm to the bite. Drain the potatoes and place in a bowl.
Peel the onion and apple and cut into small cubes or mix. Add both to the potatoes and season and top with honey and mustard. Stir in the sour cream and serve the salad.
Tip: Other ingredients can include spring onions, chives, radishes, peppers, eggs and tomatoes.