On the recommendation of a friend, decided to go to Sunday brunch here. You definitely need a reservation if you go before 1pm. We made one for 10am, thankfully, as it was packed. We sat in the back of the main room, which gave us an opportunity to catch up and actually hear each other. It didn’t get too loud, which was a small miracle given the amount of people. (There is outdoor seating, which was a great thing to have, as this weekend in Frankfurt has been absolutely beautiful.) The main room is quite small, which was somewhat inconvenient because there is not enough space at peak brunch hour for people to form a proper lunch for the buffet. Even though we were tucked away in the corner the line came all the way to us and was a tad disruptive. All in all, a minor inconvenience.
The food itself was phenomenal. Authentic German cheeses and breads (!) which were incredible. My friend is a strict vegetarian and had plenty of options. I would definitely return, though I’d probably go mid afternoon just so it wouldn’t be so crowded.
It’s very easy to get to; about 2 or 3 blocks from an U-bahn station (specifically the U5 line) about three stops past Konstablerwache.