Ah, a true comfort food dessert I have tried out with some new twists...but the traditional version is also quite wonderful. This is a northern German dessert with red fruits. Often this is made with currants and berries, but also with plums. One of my versions used plums: an organic cherry plum, santa rosa plums and a few Japanese shira plums. Add cranberries and raspberries for good red fruit contrasts. If you make an all yellow fruit version, then it is Gelbe Grütze. Mirabella and yellow raspberries work well for that. Sapa (http://www.nudo-italia.com/categories/4) and sumac really enhance the flavors of the plums. See my recent recipes for more background on those. You can make this without those and still savor.In larger batches you can also process and can. Canned Rote Grütze makes a great holiday gift. I first had this in the restaurant at KaDeWe in Berlin with my sister. It quickly became a family favorite. Warm plums make a luscious version. Since the first batch that I made was gone so quickly, there has been a cry for more. So I just made another batch adding in some roque blueberries and red raspberries which you can see cooking in the pot of the last photo. Cranberries are great for a festive addition. —Sagegreen
Heat a heavy sauce pan and add the sumac and cinnamon to it for half a minute. Add the lemon zest for half a minute. Make sure your pan choice will not be reactive with the fruit.
Next add fruit, sugar and honey and bring to a slow boil to a slow boil: Stir often. The juices from the plums should prevent any scorching, but keep watch.
If you want to use a thickener mix the arrowroot in with the sapa. If not using sapa, then add the arrowroot to some water. Traditional versions use cornstarch. I prefer to add no thickener at all, but just to reduce the sauce by simmering.
Add the sapa and wine to the plums. Simmer for 5 minutes. Continue cooking and reducing until the sauce thickens to your liking. You can remove the skins of the plums after cooking and cooling, rather than before...I think it is easier. I prefer this less thick. I also would usually not puree mine.
Let cool and store for 24 hours to let all the flavors set. Serve warmed with vanilla ice cream, vanilla custard sauce, or dollops of whipped cream. Or if you can't wait, you can eat it warm right away, too.