Preheat oven to 325°F. Butter 9-inch-diameter glass pie dish. Sprinkle raisins in prepared dish. Whisk 1/2 cup powdered sugar, yolks, egg, flour and salt in medium bowl until blended. Whisk in cream, then milk; pour custard over raisins.
Bake clafouti until set in center, about 40 minutes. Sift remaining 1 tablespoon sugar over. Let stand 15 minutes. Cut into wedges and serve warm.
