Airside chocolate is very expensive in Germany relative to real world German pricing. Fortunately, there are two Edeka and one Müller at MUC landside which are easy to reach on a layover. FRA has two grocery stores (the Rewe City is the better of the two, but neither are as convenient as the stores at MUC) The ordinary, run of the mill chocolate tends to be considered head and shoulders above American chocolate, but it's to us just ordinary. There are however great ranges of midrange chocolate including a good variety of alcohol filled ones.

And not on airport, but if near SZG then one can make a quick run across the border to the Reber factory where they have a kiosk onsite including factory seconds.

It's all relative as I've never found anything worthwhile at AMS or BRU for instance, yet some of you seem to rave about it.