Are you doing a solid ice cream cake? If so, use a springform pan and place a cake circle at the bottom. Spread vanilla ice cream around the sides, no matter what other flavors you are using, because the color will show through. Allow it to freeze after the sides are covered with vanilla ice cream, then you can fill the pan with other flavors. Freeze after each flavor. If you are putting filling in the middle, allow it to freeze, too, before adding another layer of ice cream. When you reach the top of the pan, level it by using a long spatula to spread the ice cream. This will be much easier to do if you are working with softened ice cream. Allow the cake to freeze for several hours. To unmold, run hot water along the sides of the pan. Set the pan on top of a bowl smaller than the cake pan, undo the latch and push the sides of the pan down.