Plum Butter (German Pflaumenmus)
from https://www.daringgourmet.com/

This Plum Butter recipe, known as Pflaumenmus in Germany and Powidl in Austria, is made in the slow cooker for an incredibly deep, rich, caramelized flavor. It’s easy to make and if canned properly will keep for up to a year. It’s delicious on bread, toast, muffins, scones, waffles, pancakes, added to cakes and pastries, and even served with grilled meats and seafood! Or incorporated in your favorite BBQ sauce.

Plum Butter brings back memories of the time I spent with my Oma and Opa growing up in southern Germany. There it’s called Pflaumenmus and you can readily find it in any grocery store next to the jams and marmalades. My Oma used to make Kartoffelpuffer (potato pancakes) and we would eat them with apple sauce (Apfelmus) or Pflaumenmus. She would also use it as a filling for one of my favorite Swabian dishes, Dampfnudeln: Sweet yeast dumplings filled with fruit and served drizzled with brown butter and hot vanilla custard.

Italian plums (aka, European plums) are used for plum butter in Germany. Unlike all other varieties of plums, Italian plums are especially suitable for cooking and develop a nice, complex flavor in the process. Their season is very short, usually September through early October, so take advantage of them while you can.

This version is for the slow cooker but in Germany plum butter is most commonly made by baking it in the oven in a heavy pot with lid closed, usually around 350 F for 2-3 hours. The oven method produces a little different texture, a slightly more jam-like consistency versus the consistency of apple butter.

[Cook chopped up plums with a little water until it gets going in a pot over medium high until it starts thickening and sputtering. Then start adding sugar to taste, no cinnamon or cloves are used and then put it in a glass dish for the oven. Bake at like 300-325. Once the surface is darkening and forming a skin, stir it up and put it back in the oven until it is reduced and very rich and dark. It should hold a mounded shape when dropped from a spoon onto a plate, not a puddle like apple sauce. The texture will get finer and finer as it bakes. Plums are plenty tart but maybe have a lemon ready to perk it up if you need to, and a bit of salt.

Another recipe just cooks it on top of the stove. ]

A note on sugar: The plums themselves can be safely canned without the addition of any sugar (most fruits, including plums have enough acidity to be safely canned without anything added to them), so that means you can freely use as much or as little sugar as you prefer.

6 pound Italian plums ,halved and pits removed
4 cups sugar ,or combination of white and brown sugar
1 1/2 teaspoons ground cinnamon
1/2 teaspoon ground cloves

Place the plums in the slow cooker. Stir in the sugar, cinnamon and cloves. Cook either on LOW for at least 10 hours or on HIGH for at least 4 hours until the plums are very soft.

Use an immersion blender (or transfer to a blender, puree and return to the slow cooker) to puree the plum butter until smooth. If you prefer it a little chunky, blend until the desired texture is achieved.

Continue to simmer the plum butter, this time with the lid opened, until the plum butter is reduced in volume to a spreadable texture, approximately 5-6 more hours on LOW or 3-4 hours on HIGH. (Note: The longer you simmer the plum butter the more deeply caramelized it will be. If you're going to simmer it for a much longer time, I recommend doing so on LOW to prevent burning. I’ll often simmer it with the lid closed for up to 20 hours and then open the lid, puree it, and simmer for another 5-6 hours until thickened.) Once it's reached the desired consistency, taste it. You can add more sugar at this point if you prefer and let it simmer until the sugar is dissolved.

For Canning: Pour the hot plum butter into sterilized jars leaving 1/4 inch headspace. Wipe the rim and secure the lids. Boil in a water bath canner for 10 minutes. Remove the jars and let them sit undisturbed for 24 hours before transferring them to a cool, dark place for long-term storage. Will keep opened in the fridge for up to 2 months.

Makes approximately 4-5 pints depending on how long you cook and reduce the plum butter.