In a 9-inch cast-iron skillet, combine the plums, nectarines, raspberries, water, lemon juice, cornstarch and 5 tablespoons of the granulated sugar.
In a bowl, blend the flour with the baking powder, baking soda and the remaining 1 tablespoon of granulated sugar. Stir in the buttermilk and melted butter.
Bring the fruit to a boil. Reduce the heat to low. Drop the batter by tablespoons on the bubbling fruit. Sprinkle the brown sugar over the batter. Cover tightly and simmer for 13 minutes. Remove from the heat, uncover and let cool to warm or room temperature. Garnish with the cinnamon basil and serve.
One Serving Calories 362 kcal, Total Fat 6.6 mg, Saturated Fat 2.8 mg.