While visiting Markus Müller at the Institute for Theoretical Physics at the University of Heidelberg to work on on our paper with Cozmin Ududec, I strolled all the way through the old town from my hotel on Bismarckplatz, past the Holy Ghost church on the market square, throught the Karslplatz with the illuminated castle ruins looming on the hillside above, and on down the less frequented end of the Hauptstrasse to the Restaurant Zur Herrenmuehle.  It was well worth the walk.  In a former mill, from the 17th century (hence the name "at the old mill", or maybe "at Old Man Mill").  I had the four course version of the Landhausmenu.  I tend toward vegetarianism with some fish, but am not completely strict about it, and suspended it here:  there was a little bit of salted beef in the soup course, and the main course was venison.  I suppose I rationalized it a bit by thinking that the deer at least run around free for most of their lives, rather than being cooped up in feedlots for a good chunk of them.  The first course, if I recall correctly, was marinated salmon (essentially lox) with anise and pepper, pickled mango, and asparagus; the second was a smooth foamed pearl-onion soup with whole pearl onions and a few salt-cured beef slices; excellent, concentrated flavor (would have been excellent even without the beef).  These went very well with a "Trocken" Riesling, Kabinett I believe, but I've forgotten the producer.  (One of the Rhine regions, I think.)   "Trocken" means dry, and refers to a more typically international method of winemaking that foregoes the traditional German süssreserve (sweet reserve) of unfermented wine added to end fermentation.  This wine, however, tasted closer to a traditional German style than your usual West Coast US or Alsatian Riesling.  The main course involved rare roasted or grilled venison and brussels sprouts flavored with real vanilla bean (a stroke of genius), as well as other delicious stuff.  The final course was semolina pudding slices with pistachios, etc...  When I ordered a glass of red wine to go with the venison, I mentioned two of the wines by the glass--neither German---that I was considering.  The one I didn't mention was a Spätburgunder, a German pinot noir.  The waiter recommended I have the Spätburgunder with the venison, and he was absolutely right.  While still recognizably a little bit sweet and fruity (a style that can be annoying in Spätburgunder if done clumsily, which is why I was not considering it initially), it was balanced, rather velvety and refined, with a kind of graham-cracker-like texture to the somewhat softened tannins, and a little bit of minerality and complexity in addition to beautiful strawberry-ish fruit.  Perfect complement, in the echoing-with-subtle-differences mode, to the venison.  I love it when a restaurant knows what wines go with their dishes, and isn't afraid to tell you.  I asked about the producer, and recall that it was fairly local, somewhat to the south of Heidelberg, I believe.  But I didn't jot down the name, unfortunately.  Probably one of those superb small local producers whose output is all spoken for by the local restaurants, wineshops, and customers, and not to be found in the US anyway (plus Spätburgunder may not be the best-traveling wine, freshness being a big part of its appeal).  I ordered a brandy rather than a coffee as an after-dinner-drink, and ended up with a surprise, a Spanish brandy (wish I could recall the producer!) that was a glorious end to the meal, and turned out to be complimentary.  The interior, as you can see by some of the pictures on the website, is elegant but still retains some of the rusticity of the old mill, for instance the wooden beams, and the bench seating around the edge of the room, even if not part of the original mill, lends a slightly rustic touch too.  Service was perfect, friendly and not obtrusive, and everyone there obviously loves good food and is happy to be providing it at a really high level.  I don't know if this restaurant has a Michelin star but I would definitely give it one (at least).  This is one of those places that should be known to all in the international fraternity (sorority, egalité) of lovers of fine food matched with equally fine wines... it is obviously owned, run, and staffed by members of the same.