- 7 tablespoons unsalted butter, chilled
- 7 tablespoons light brown sugar
- 5 cups ripe but firm plums, pitted and sliced into 1-inch wedges (6 to 7 plums)
- 1 1/4 teaspoons salt
- 6 ounces blackberries
- 2 tablespoons finely chopped crystallized ginger
- 2 teaspoons lemon juice
- 1 teaspoon cornstarch
- 1 1/2 cups all-purpose flour, plus additional for dusting counter
- 1 1/2 teaspoons baking powder
- 1 1/2 teaspoons ground cinnamon
- 1/4 teaspoon baking soda
- 3/4 cup buttermilk, chilled
Melt 3 tablespoons butter in large skillet over medium heat. Add 1/4 cup brown sugar and cook, stirring, until dissolved, 1 to 2 minutes. Add plums and 1/4 teaspoon salt and cook, stirring occasionally, until they begin to release juices, 3 to 5 minutes. Increase heat to medium-high and continue cooking and stirring until juices are thickened, 3 to 5 minutes.Stir in blackberries and ginger.
Stir lemon juice and cornstarch together in small bowl and stir into fruit. Transfer fruit to pie plate.
Adjust oven rack to middle position and preheat oven to 425°F. Stir together flour, remaining 3 tablespoons sugar, baking powder, remaining 1 teaspoon salt, and baking soda. Cut in, or pulse in food processor, remaining 4 tablespoons butter until mixture resembles small peas. Stir in buttermilk, mixing just until combined.
Dust clean, dry work surface with flour and turn dough out onto surface. Knead just until dough comes together, about 6 times. Pat dough into approximately 8-inch circle and stamp out biscuits or cut dough into wedges.
Top fruit with biscuit dough and bake until biscuits are golden, 20 to 25 minutes. Transfer to cooling rack and cool about 10 minutes. Serve warm with optional ice cream or drizzle of fresh cream.