Potato Salad

600 g potatoes (firm)
60 g onions
250 ml beef stock (cube)
3 tbsp. vinegar
6 tbsp. vegetable oil
1/2 tsp. Estragon mustard
salt, pepper, a pinch of sugar



Cook the potatoes with their peel, remove peel and cut into thin slices into a bowl, while still warm. Cut the onions into small cubes. Heat the soup and immediatley pour over the potatoes. Blend in the vinegar, oil, onions, salt and pepper until it gets a creamy consistency. Season to taste with mustard and sugar. Let it sit a little bit before serving.