Wash potatoes. Cut medium ones in half and large ones in quarters. Steam for 15-20 min. Let cool, remove the skins. Refrigerate cooked potatoes in a covered container for a few hours until starches are completely set.
Wash carrots. Cut the long ones to fit your steaming pot. Steam for 15-20 min, until soft, but not overcooked. Let cool, remove the skins. Refrigerate cooked carrots in a covered container until ready to cube.
Wash beets. Cut medium ones in half and large ones in quarters. Steam for 15-20 min, or until soft, but not overcooked. Let cool, remove the skins. Refrigerate cooked beets in a covered container until ready to cube.
Steam large eggs for 8-10 min. Meanwhile, prepare an ice bath in a large bowl by filling it with ice and cold water 1:1. Ice shock steamed eggs for at least 5 min. Shell them. Refrigerate shelled eggs in a covered container until ready to mince.
Wash and chop scallions, both white and green parts.
Cube potatoes, season with salt and black pepper to taste, and mix with 2 tbsp of mayonnaise in a separate bowl. Do the same with carrots and beets, each vegetable in its own bowl. Carrots and beets can be grated instead of being cubed.
Mince salted herring and keep in a separate container. Mince eggs and keep them in a separate container.
Prepare 2 deep, round, 1-quart containers. Line their bottoms with parchment paper. Assemble the salad by making 1/4" thick layers of all prepped ingredients. In my version, the layers from the bottom — scallions, potatoes, herring, carrots, beets, eggs, scallions, herring, potatoes. Cover filled to top containers with a lid or plastic wrap and refrigerate for at least an hour before serving.
Watch the video to see how to serve the salad.