I completely understand your preference for the classic version. While modern variations often introduce ingredients like grated tart apples, melted butter, or cheese, the traditional Soviet-era recipe relies strictly on simple root vegetables, eggs, and salted herring.
To build the authentic salad from the bottom to the top, begin with finely diced salted Atlantic herring fillets. Immediately over the fish, add a layer of finely chopped yellow onion. If the onion is very sharp, blanching it briefly in hot water or soaking it in cold water with a drop of vinegar softens the bite without altering the classic profile.
Next comes a layer of boiled, peeled, and coarsely grated potatoes. Lightly season the potatoes with a pinch of salt and spread a thin, even coat of mayonnaise over them. Follow this with a layer of boiled and coarsely grated carrots, followed by another light layer of mayonnaise.
After the carrots, add coarsely grated hard-boiled eggs with a light spread of mayonnaise. Some traditional households place the eggs directly over the potatoes before the carrots, but both variations are completely authentic to the original preparation.
The final top layer is boiled or baked beets, peeled and coarsely grated. Spread mayonnaise generously over the entire top and sides to seal the dish and create the signature vibrant purple coat.
For the best texture and flavor, cover the dish and let it chill in the refrigerator for at least six to eight hours before serving. This allows the root vegetables to absorb the mayonnaise and the flavors to properly harmonize.