How to Make It
Prepare the Filling: Combine water and sugar in a 12-inch cast-iron skillet with lid over medium-high. Bring to a boil, stirring until sugar dissolves. Add plums and fresh ginger; cover skillet, and bring mixture to a boil. Reduce heat to medium-low, and simmer, covered, 10 minutes.
Prepare the Dumplings: Whisk together flour, sugar, baking powder, and salt in a medium bowl. Add whole milk and melted butter, stirring until batter is combined and smooth.
Remove lid from skillet, and drop rounded spoonfuls of batter evenly over ginger-plum mixture. (You should have 10 Dumplings, about 2 tablespoons each.) Reduce heat to low; cover skillet, and simmer until a wooden pick inserted in center of Dumpling comes out clean, about 20 minutes.
Prepare the Topping: Combine heavy cream and powdered sugar in a medium bowl, and beat with an electric mixer on high speed until soft peaks form. Serve slump warm in shallow bowls. Top each serving with a dollop of sweetened whipped cream, and sprinkle with chopped crystallized ginger.