Sauerkraut

The problem with that is there are two types of it - the sweet one and the sour one. In a restaurant you'll usually get the sweet one which I think is tastes awful.

But the sour one is the really good one especially if you refine it by adding fine cubes of Kassler (smoked pork chop) to enhance the taste. Sour Sauerkraut should even change the taste of potatoes that sit in its... sauce? broth? (don't know the word). I could eat kilos of it.
You'll need to look out for the right kind of Sauerkraut in the supermarket. Not everyone of them is suited for this.