The shiny top of the cake will not readily absorb syrup. If you do not cut it off, you might find dry spots in your tiramisu. But don't throw the top out! Crumble it into crumbs and place them in a 150 degrees F to 200 degrees F oven until thoroughly dry and crunchy. Use to decorate the top of the tiramisu, or save them to add to cookie batters or to scatter in pies and tarts to absorb juices.