This is my favorite Frankfurt specialty. The name may sound a bit odd, but it is absolutely delicious and you won't be able to find this on a menu anywhere but in Frankfurt and a few of the surrounding towns in Hessen.
Green Sauce or Grüne Sosse, is a mixture of 7 specific herbs, chopped fine, and most often mixed with a combination of sour cream, joghurt or creme fraiche (some use mayonnaise; but not purists), a bit of oil, vinegar, and mustard, salt and pepper and then served over boiled potatoes with a couple of hard-boiled eggs. It often has chopped up eggs in the sauce itself. The best sauce is made by chopping the herbs with a knife and not with a blender or food processor as it changes the taste of it. Traditional Frankfurt restaurants may offer it with tender, boiled beef, but it can be a full meal with just the potatoes. One of the more popular menu items that you can try is a "Frankfurt Schnitzel". This is a schnitzel topped with Green Sauce. You may also find it on a menu served with fried fish or salad.
The herbs can change a tiny bit due to the seasons, but traditionally it is always: parsley, chives, cress, sorrel, chervil, borrage, & salad burnet. Dill is never a substitute, but broad leaf plantain or dandelion greens can be substituted. Most of the herbs are grown in the Oberad neighborhood of Frankfurt so it is truly a local dish. We even have a monument in Frankfurt to this yummy dish - 7 little green plexi-glass houses, each one with the name of one of the herbs engraved inside and lit up at night.
There is a lot of contention about when & where Gruene Sosse originated, but all the signs point to the Huguenots who immigrated to the Frankfurt area to escape being persecuted in France. It supposedly dates back to at least the 1800's and though Frankfurt legend says that it was a favorite dish of Goethe, there is no evidence to support this. It does make for a good story.
People take their Gruene Sosse seriously. There are organizations that have succeeded in getting EU protection for it, that it can ONLY be made of these 7 herbs with no substitutions and that you can only sell it as "Frankfurt Gruene Sosse" if 10% of the herbs have been grown in Frankfurt.
Though you can get the herbs all year round, the traditional season is from Green Thursday (the day before Good Friday) until the first frost. At the Farmers markets or in the Klein Markt Halle, it is sold in white paper packets and the vendor will usually unroll it for you so you can see if it has enough of all the herbs to suit you. I often get an extra bunch of chives to add to it, as I like that flavor. It will have a different taste depending on the method used, knife, blender or food processor and it will also taste different in every restaurant as everyone seems to have their own recipe for it.
To make your own, you can use any combination of sour cream, cream fraiche or joghurt, your herbs chopped fine, a bit of mustard, a little vinegar, salt & pepper, and some hard boiled eggs.
On our walking tour, when we go through the Klein Markt Halle, you will see the white packets of herbs as well as the finished product at some of the stands. I tell people who are unsure if they will like it or not, that if they enjoy sour cream and chives on baked potatoes than they will probably enjoy Gruene Sosse too. So, I hope you will be adventurous and try this wonderful dish. Chances are good, that it will make you want to keep coming back to Frankfurt again and again, just to have some more. Now of course, you know my secret reason for living here: it's the Gruene Sosse!
Frankfurt has a Grüne Sosse Festival every year to see which restaurant makes the best one.
Grüne Sosse Fest