When Tasha and I were last in the Dresden area, we seemed to encounter Soljanka whereever we dined. It didn't matter if it was a concession stand at a national park or a classy restaurant; everybody seemed to regard this as essential Saxon comfort food. Soljanka is a Russian soup that it seems like the East Germans adopted and adapted to their taste. It's kind of like a hot and sour eastern European soup when it's done right, but this recipe doesn't have much heat per se; I'd like to experiment on that, but for the moment it's great in this form.
I doubled and translated this recipe from here after trying another that had no sourness at all. The secret, I think, is just putting pickle juice in it. That kind of makes sense, and the effect of that acid cutting through the sausage is divine. Make sure you don't forget the dollop of sour cream when you serve -- for bonus points, a slice of lemon on top in addition to the cream looks wonderful. You can also squeeze some lemon juice in your serving if you wanna up the sourness, I usually do.