Growing up in Pennsylvania Dutch country, I ate lots of apple butter, enjoying its spicy rich flavor. This summer I've been having fun using seasonal fruit to make jam and chutney. Plums are at their best now, so I decided to try a "butter". Epicurious provided a skeleton recipe but I added ingredients and adjusted cooking times to insure success. If you are new to canning, this recipe is perfect for your debut. Pick up a book on canning basics, such as the Ball "Blue Book of Preserves". Your local grocery store will sell cases of jars that include lids, screw tops and labels. For me, canning is a satisfying and comforting experience, reminding me of summers past when women in my family would "put up" their jam, chutney, tomatoes and pickles. —Lizthechef
Freeze two small plates or saucers for testing later.
Pit and cut plums into eighths. Set aside.
Zest and juice the lemon. Add to plums.
In a large Dutch oven, add the chopped plums and all other ingredients except for the Grand Marnier. Bring mixture to a boil, reduce heat to medium, and cook until fruit is very tender, about 15 minutes.
Discard the vanilla bean. Using a food processor, puree batches of the butter, taking care not to over-process. Return pureed butter to Dutch oven.
Cook butter over low heat for about two hours, stirring frequently to prevent butter from sticking to the bottom of the pot. Test for "doneness" by using one of the saucers. Spoon a little butter on it and tilt the plate. Butter should do a slow slide rather than a quick run off.
Turn off the heat, move pot to a cool burner. Stir in the Grand Marnier.
Funnel into sterile jars and process in hot water bath for 15 minutes, using safe canning procedures.