Michelle’s discovery that most any fresh fruit juice can be used to flavor buttercream has created a bit of an unusual cake boom here in Gourmandistan. While handing over a hoarded, frozen slice of our white cake with wild blackberry buttercream to her mother, Michelle casually created another cake, this time with chocolate and red plum buttercream.
Halved, heated and mashed on the stovetop, the reddish-purple beauties released their sweet-tart goodness, which Michelle added to her standard buttercream recipe. Though Michelle hasn’t found a chocolate cake recipe good enough to share, the chocolate made a nice base for the delightfully tart buttercream. And a layer of chocolate ganache and plum jam made for extra decadence.
Place plums in a small saucepan. Warm over low heat, mashing with a potato masher or a wooden spoon to extract as many juices as possible. Strain through a fine-meshed sieve, pushing with a spoon to remove all juice. You should have about 1/3 cup of juice. (If there’s more, all the better—just save for another use.) Chill in refrigerator. Add enough milk to the chilled plum juice to make 1/2 cup of liquid. Place butter, 4 cups of sifted confectioners’ sugar and liquid in the bowl of a stand mixer. Beat until smooth. Add additional sugar, one cup at a time, until thick, smooth and spreadable. (It usually takes about 6 cups.)
RED PLUM BUTTERCREAM
Add enough milk to the chilled plum juice to make 1/2 cup of liquid.