Stacking tiered wedding cakes creates a traditional, elegant appearance for large cakes. Pillars can be added between every tier, or just to separate the top tier from the rest of the cake. To ensure that the upper tiers don't crush the bottom layers, it's important to add support to the cake using separator plates and wooden dowels or push-in pillars. Once you decide how you want your cake to look and which tiers will be separated with pillars, stacking your cake is fairly simple.
Buy separator plates that are the same size as your cake tiers. Separator plates are plates that will sit below each tier, so the plate should be the same size and shape as the tier it will support. This means you will need to have several different sizes of separator plates, one for each tier of the cake. Separator plates that will sit on top of pillars should have feet on the bottom of the plate to help them attach to the pillar. These plates are available at cake speciality stores or on cake decorating web sites.
Center the bottom tier of your cake on a display board. Using the separator plate for your second tier, lightly trace the perimeter of the smaller plate in the frosting on the top of your bottom tier (this will give you an outline of where the second tier will sit over the bottom tier). Mark four evenly spaced dots just inside the perimeter of your traced circle.
If you want your cake to have pillars between each tier, insert four push-in pillars on top of the marked dots. Push the pillars all the way to the bottom of the cake, so the pillar is touching the display board.
If you want your bottom tiers to be stacked without pillars, insert a wooden dowel into your first marked dot and press the dowel down to the display board. Mark the spot where the top of the cake meets the dowel. Remove the dowel from the cake, and use a handsaw to trim four dowels to the marked length. Insert all four trimmed dowels on the marked dots from step two, so the dowels are completely submerged in the cake. The top edge of each dowel should be even with the cake's surface, so the top of the cake is perfectly flat with four small wooden circles where the top of each dowel is visible.
Lay the separator plate for the second tier on top of your pillars or dowels, centring the plate so it is evenly supported by all four posts. If your plate is sitting on top of pillars, centre the plate's feet on each pillar. Set your second tier on top of the separator plate.
Repeat steps three and four for each subsequent tier, pushing your dowels or pillars down to the separator plate instead of the display board. As the tiers get smaller, you can reduce your dowels or pillars to three and eventually two per tier. The top tier does not need any dowels or pillars; once the second-to-last tier is finished, you can place the final separator plate and set the top tier in place.