Preheat oven to 375* F. Brush madeleine molds with soft, not melted butter; dust molds with flour. In a medium bowl, beat together eggs, 1/3 cup sugar and vanilla with, mixer at high speed until blended. Fold in cooled butter. Spoon batter into buttered and floured madeleine molds. filling almost to the top. Bake 10 to 12 minutes or until cookies spring back when touched with your fingertip. Remove cookies from molds, cool on racks. While warm, sprinkle with sugar.