Peel the carrot and apple, grate them finely and place in a bowl with the sauerkraut. Cut the onions into fine cubes, chop the parsley and add to the sauerkraut. Mix with 2 tablespoons of oil. Finally, season the salad with the sugar.
I usually take about 2-3 tablespoons, it always depends on the acidity of the sauerkraut!
Let the salad steep for about 1 hour and then season again to taste.