Instructions:

1. Place the unpeeled potatoes and carrot in a large pot. Add a bit of salt, cover with water, and bring to a boil. Cook over medium heat until tender (about 30–40 minutes). Once cooked, cool the vegetables in very cold water, then peel.
   
2. While the vegetables are cooking, peel the onion and chop it finely in a blender.
   
3. Roughly chop the herring and add it to the blender with the onion. Blend until well combined.
   
4. Transfer the mixture to a container, add the oil from the herring, mix well, and let sit for at least an hour.
   
5. Meanwhile, bring a small pot of water to a boil for the eggs. Once boiling, add a pinch of salt, cook the eggs for 15 minutes, then cool them in very cold water. Peel and grate the eggs on a medium grater. Add 30 g of mayonnaise, salt to taste, and mix.
   
6. While the eggs cook, peel and grate the beets on a large grater. Add 60 g of mayonnaise, salt to taste, and mix.
   
7. Mash the potatoes with a fork or use a potato ricer. Add 60 g of mayonnaise, salt to taste, and mix well.
   
8. Grate the carrot on a medium grater, add 20 g of mayonnaise, and mix.
   
9. Layer the ingredients in this order: herring with onion, potatoes, carrots, eggs, and beets. Optionally, spread a thin layer of mayonnaise on top.
   
10. Chill the salad in the refrigerator for several hours or overnight for best flavor. Before serving, let it come to room temperature for about 20 minutes.