All cakes must be trimmed at the very least on the top and bottom before being stacked into layers for a cake. The upper crust is nearly always domed, and the bottom layer is always a bit darker than the interior. A perfect layer should appear consistent in texture and color throughout as well as perfectly flat and level. Torting is the term used for trimming, leveling, and slicing into even layers. There are tools available to assist in performing this task, but all that is really necessary is a steady hand and a long cake knife.
Get Eye-Level: Position the cake on a level surface large enough to rest your cutting hand to one side while holding the knife where the dome begins to rise up from the edge of the cake.
Trim: Use your knife to just lightly mark into the cake horizontally, adjusting as necessary to make a complete circle. Rotate the cake while holding the knife level by resting and sliding your hand forward and back on the table. The cake rotates; the hand stays in a static position. Cut into the cake incrementally towards the center.
Tort into Layers: Carefully flip the cake over and repeat this process to the bottom layer. If creating multiple layers, divide by marking around the cake in a circle. It can be helpful to use a guide such as toothpicks until proficient.
Torting can be a bit challenging if your cake is particularly moist (carrot cake) or spongy (angelfood cake), or baked unevenly, and it certainly does take some practice. Work patiently, slowly and carefully; speed will come with gained experience.
Creating these even layers gives the sturdiest foundation and is paramount to a successful build.
The key to a sound structure is even layering throughout. Using minimal supplemental interior supports should be a goal in the build. For tiered cakes, “topsy-turvy” cakes, carved cakes, or double-tiers, interior supports will be necessary. For all other designs, the stability relies on choosing the correct cake and frosting for the desired outcome, and manipulating those components into even and stable layers.
Building a Solid Foundation
The bottom cake layer is the foundation; it should be the sturdiest of the torted layers, and is most often the one which began as the bottom of the baked cake.
Preparing the board: A dollop of frosting in the center of the cake board will stabilize the first layer. Smooth the frosting into a disc which will be visually discrete when the completed cake is sliced, but enough to secure the layer for ease of building.
Beginning the build: Place the first cake layer centered on the frosting. As this is the foundation, it is most important that this layer is well intact and perfectly level.
Adding the Filling layer: The filling layer is just as important in stabilizing the structure as the cake layers. Using a ‘damming method’ for a loose or soft filling will keep the build stable. The choice of frosting for the internal build should match the weight of the cake choice. Dense, heavy cakes or thick layers will require a sturdy frosting, where lighter fillings can successfully be used for airy cakes or thin layers. Pipe or smooth with an offset spatula to the edge of the layer.
Damming: Using a piping bag with a large plain tip, create concentric circles with a firm frosting. It is important to have the frosting just at the edge of the layer and in the very center of the layer. For large layers, circles of frosting are evenly spaced to hold the soft filling while providing necessary support to the layer. The outer dam and the center support of frosting are the minimum for the damming method to be effective. Lightly smooth this layer.
Stacking the layers: Gently place the second cake layer over the filling layer. Be certain that this cake layer is even and level. It can be helpful to use a cake round to gently press to adjust.
Repeat the process: Continue the process of creating even and level layers of cake and filling/frosting. When completed, lightly run a spatula around the side of the structure to clean up the frosting which is protruding outside of the layers. It can be helpful to chill the build at this point if the cake is tall, or if the filling/frosting is on the softer side. It is easier to apply a crumb coat to a firm structure.
Applying a Crumb-Coat: Use an off-set spatula, scrape a thin layer of frosting lightly around the sides of the cake to fill in any areas missing frosting, and lightly over the top layer to seal and create a flat surface. This thin coating will capture any stray crumbs, fill in holes and create a flat, smooth surface for the final decorative frosting.
Chill the Structure: Refrigerate the cake until the crumb coat has set. The entire structure can be wrapped at this point to protect it from absorbing off-flavors from the refrigerant if the cake is not being completed within 24 hours. The cake should be patted dry with paper towels after unwrapping to remove moisture before applying the finishing frosting.