So...

In short, Emma Metzler was fantastic: Perfect distance from the train station, exciting, inventive German-European cuisine, great wines and the price was right!

They offer three different pre-fix menus -- vegatarian, meat/poultry, fish -- and a choice of 2 or 3 courses for each. I had the 3-course fish menu, which cost 26.50 Euros.

I would call the first course an amuse bouche, but really it was a more substantial dish than that, more like an appetizer: A serving of "taramasalata" made with creme fraiche (super light and airy, much less fishy than the normal, Greek variety), served with bitter pea shoots, a rice wafer and balsamic reduction. I loved this dish - the creamy saltiness of the tarama was perfectly offset by the spicy bitterness of the pea shoots. Bonus!

Second course was celery soup with anise foam. It's hard to describe how intriguing this tasted: there was a fullness, almost chewiness to it -- very earthy, a little sweet. I would never have thought to pair celery and anise, and the combination was something much more than the sum of its parts. I savored every drop of this soup. Definitely pushed the edge of the envelope!

Third course was a tender piece of herb and sesasme encrusted cod, served with a leek, tomato and asparagus ragout, saffron foam and jasmine rice. A lovely dish if not as inventive as the previous ones.

Dessert was a buttermilk biscuit "donut" (it was glazed in icing!) with buttermilk icecream, berries and a white chocolate tuile. I liked it a lot -- even though I was near bursting at this point.

Given the extensive German wine menu, I put myself in their hands and was not disappointed: They served me a crisp, mineral, tinge of floral riesling -- very unlike the sweeter rieslings I'm used to drinking in the states. If complemented the pre fix perfectly.

My only regret is that I didn't order off the main menu as well! There were at least 3-4 entrees I regret not being able to try!

I have to give kudos to david7031 for the great reccomendation! An attractive restaurant with serious, inventive food. I'm definitely going back the next time I have a Frankfurt layover...and I highly reccomend it to anyone else looking for a layover lunch. ^^^^