Whether the tiers are round, square or rectangular, you will need to make sure each tier of your three-tiered cake is independently and well supported. Cake tier plates are made to lock together tightly with supporting columns, which are usually sold separately. Columns come in a variety of styles to suit your cake, if you decide to leave them exposed and integrate them into your overall cake design. If you want the tiers to look as if they are stacked right on top of each other, choose shorter columns that will be completely hidden by each tier of cake.
Write down the sizes of your cake tiers to take with you to the craft or baking store. Choose cake tier plates that are the same size as your tiers; a 9-inch circular tier needs a 9-inch circular cake tier plate, and a 9-inch square cake needs a 9-inch square cake tier plate.
Measure the height of each cake tier to determine how tall your columns should be. Decide how much (if any) column you want exposed. If you want none of it exposed, choose a column height that is the same as that particular tier of cake.
Place the bottom cake tier plate on the counter. Slide the bottom tier of cake gently onto it and centre it.
Connect the columns that will go between the bottom and middle cake tier plates to the base of the middle cake tier plate. Make sure they are completely connected and do not feel at all loose or wobbly.
Line the middle cake tier up visually on top of the bottom cake tier and be certain of where you want it. Stab the four columns on the bottom of the middle cake tier plate through the bottom tier of cake. Do not stop until you feel the columns reach the bottom, underneath the actual cake.
Slide the middle tier of cake onto the middle cake tier plate. Repeat the process of mounting the remaining four columns to the base of the top cake tier plate, then placing it on top of the middle tier. Slide the top tier of cake into place on the top cake tier plate.
Fix any smudges or other visible mistakes with extra frosting.
Professional cake decorators apply a smooth base coat of frosting (or fondant, if you are using it) before putting the tiers of cake together. They then complete decorations (such as flowers, shells, or other sugar and gum paste decorations) once the cake is together so that they can more easily correct any accidents that may have occurred when assembling the tiers.
Unless you have some way to safely transport a three-tiered cake to wherever it will be served, it is best to assemble it on site. Transporting a tiered cake can be very tricky, and may result in unintended consequences and grave disappointment. If you want a stacked cake with no spaces between the tiers, do not think that you do not need columns and cake tier plates. Cakes are heavy, and the cake will cave in if each tier is not properly supported.