Preheat oven to 375 °F.
Dice apricots, plums and peach or nectarine (with skin on) into pieces about ½-inch in size and toss with melted butter. Stir in brown sugar and cinnamon and set aside.
On a lightly floured surface, simply roll and cut puff pastry into 6 rounds. Put filling in center of each and pinch edges firmly, creating a ruffle around the edge. Place dumpling in a 6-cup baking dish. Chill for 20 minutes before brushing with egg wash.
Bake for 25 to 30 minutes, until pastry is a rich golden brown. Let cool for 10 minutes before serving.
Sprinkle with icing sugar.