Wash the potatoes thoroughly and cook in boiling water for about 25 minutes. Boil eggs in boiling water for about 10 minutes, rinse with cold water, peel. Cook peas in boiling salted water for about 5 minutes, drain, rinse with cold water and put aside.
Peel, wash and chop the carrots. Peel and chop the onion. Heat the oil in a pan and fry the onion and carrots. Add 250 ml water, bring to the boil, stir in the stock. Simmer for 6-8 minutes.
Let the cucumbers drip off and collect the cucumber water. Dice cucumbers as well. Remove the carrots from the heat and let them cool down a little. Roughly chop the walnuts. Cut sausage into strips. Drain potatoes and rinse with cold water, remove skin.
Stir mayonnaise and yoghurt into the stock. Add 5-6 tablespoons cucumber water, season with salt and pepper. Cut potatoes and eggs into cubes. Wash apples, quarter them and remove seeds. Cut apple quarters into small pieces.
Wash the chives, dab dry and cut into rings. Mix all salad ingredients together. Chill for at least 1 hour, season to taste again. Heat up Wiener sausage in hot water and add.