Preheat oven to 325°F. and butter a 2-quart shallow baking dish. Cut nectarines into 1/4-inch-thick wedges and in a bowl macerate with blueberries in wine 15 minutes. Melt butter and cool slightly. In a large bowl whisk together eggs, granulated sugar, and salt. Whisk in flour until combined well and whisk in milk, butter, vanilla, and 1/4 cup wine from fruit mixture until smooth. With a slotted spoon transfer fruit to baking dish, reserving wine for another use (such as sangria), and arrange in bottom. Carefully pour batter over fruit (the fruit will rise to the top) and bake in upper third of oven until puffed and set in center, 55 to 60 minutes. Transfer clafouti to a rack to cool. Just before serving, dust clafouti with confectioners`sugar. Serve clafouti warm or at room temperature.