For the salad, boil the egg for about 10 minutes and let it cool down. Boil the potatoes as jacket potatoes for about 20 minutes or use potatoes from the day before. Cut the matjes fillets, the cucumber, the apple, the meat sausage, the cooled potatoes and the egg into fine cubes. Also finely dice the onion and briefly scald it in boiling water so that it does not taste so intense. Mix the diced ingredients with the vinegar, ground pepper, juniper berries, mustard seeds and sugar. Salt is not necessary as the herring is usually salty enough. Put in the whole bay leaf.
For the mayonnaise, put 2 whole eggs (room temperature) with 2 tablespoons of vinegar, one tablespoon of sugar, 2 tablespoons of mustard and the salt in a tall container. Slowly add the oil while the hand blender is running until the mayonnaise solidifies. Add the finished mayonnaise to the ingredients and stir in.
The salad tastes best when it is prepared the day before. Before consumption, please remove the bay leaf and decorate with parsley if necessary.