A very serious competitor to my favorite Pink Soup, the Samogitian version is known for its superpowers when it comes to curing a hangover.
1 fillet of salted herring (ok, this isn’t exactly authentic, but trust me, you don’t want to deal with the whole herring that comes straight from a barrel);
1 l of kefir;
freshly ground black pepper;
potatoes (for serving, optional);
fat for cooking the potatoes (again, optional)
First, you need to pan-fry the herring. If, for some reason, you went with the whole thing, fillet it first. Now, turn the heat to the max and wait until your herring turns into a nice and brown golden fish (does this even make sense?). Chop the fried fish, take any bones out. Add the herring, dill, and spring onions (chopped, too, obviously) to a pot and cover with kefir. Season with black pepper and place in the fridge for at least half an hour so the flavors could get to know each other better. Done.
I think that fresh garlic wouldn’t ruin things, either. I would use a small clove for one liter of soup. A finely diced onion would add some nice flavor, too. It’s up to you to decide whether you’ll be kissing a prince or an enemy that day. Decide accordingly.