There are many different methods to ice a cake. Trying different methods is a good way to learn which works best for you. Icing a cake smoothly is not necessarily easy and may take practice to perfect. Below are two different ways to ice a cake, one using a quick icer tip and the other using thinned down icing as a “crumb coat”. If you are new to cake decorating, try both methods and see which you prefer.
Using a Quick Icer
Step 1: Follow the steps in Cake Preparation Part 1: Baking, Cooling, and Leveling and Cake Preparation Part 2: Torting and Filling. Set the cake on a cake board. Brush off the surface with a pastry brush to remove any crumbs before icing. Fit a large pastry bag with a quick icer tip (#789) and fill about 2/3 full with icing.
Step 2: Start at the base of the cake with the tip touching the surface and hold the bag at a 45° angle from the cake. Pipe around the entire base with the quick icer touching the cake the whole time. For double layer cakes or taller, start at the base of the cake and work your way up, slightly overlapping each time until you have completely covered the sides of the cake with bands of icing.
Step 3: Cover the top using the quick icer, again overlapping each strip.
Step 4: Use an icing spatula to smooth out the lines and ridges in the icing. Start on the top and then continue to the sides. Try to smooth the icing as much as you can. After the icing has formed a crust, you can use a smoothing technique to completely smooth the icing.
Using a Crumb Coat
Step 1: Thin your icing by adding a very small amount of water and mix thoroughly. Apply a thin layer of the icing to the cake. It is alright if you can see the cake through the thin layer of icing. Coat the whole cake and allow it to form a crust. This will lock any crumbs in.
Step 2: Add a large amount of regular icing to the top of the cake.
Step 3: Spread icing over the top of the cake to the sides. Hold the spatula perpendicular with the cake board and work the icing back forth all the way around the cake until the sides are covered.
Step 4: Use the spatula to smooth the icing making sure that the cake is covered. Once the icing has crusted, use one of the smoothing techniques to get a completely smooth surface.
Try any of the following techniques to get a completely smooth finish on the cake.
Smoothing technique #1: After the icing has crusted, run a pastry roller over the cake to smooth out any imperfections.
Smoothing technique #2: After the icing has formed a crust, use a paper towel or sheet of parchment paper to smooth the icing. Place the paper on the top of the cake and run a spatula across it. Hold the paper up to the side of the cake and smooth with the spatula, keeping it perpendicular to the board.
Smoothing technique #3: Before the icing has crusted, dip your spatula in hot water and wipe dry. Run the hot blade over the iced cake. The heat will help to melt and smooth as you go.
Autumn Carpenter’s book The Complete Photo Guide to Cake Decorating is a great resource to have on hand when baking and decorating cakes. The book contains detailed instructions along with pictures of different methods on icing cakes.