Put the saucepan in a bowlpartly filled with ice cubes (or pour into another bowl over the ice it will chill faster), then whisk the chocolate sauce, either manually with a whisk orwith an electric mixer (if using an electric mixer, watch closely—it willthicken faster). Whisking creates large air bubbles in the sauce, whichsteadily thickens. After a while strands of chocolate form inside the loops ofthe whisk. Pour or spoon immediately into ramekins, small bowls or jars and letset.