Yes, you can substitute cream cheese frosting for buttercream frosting on a layer cake, but there are some considerations to keep in mind.
Flavor: Cream cheese frosting has a tangy and slightly tangy flavor due to the cream cheese, while buttercream frosting is sweet and buttery. Swapping one for the other will significantly change the taste of the cake, so make sure it complements the other flavors in the cake.
Texture: Cream cheese frosting tends to be softer and creamier than buttercream. While it can be spread on layer cakes, it may not hold intricate decorations as well as firmer buttercream. If you plan to use cream cheese frosting on a cake with multiple layers or intricate decorations, consider chilling the cake before applying the frosting to help it firm up.
Stability: Buttercream is generally more stable in warmer conditions compared to cream cheese frosting, which can become softer and more prone to melting at room temperature. If the cake will be displayed or served in a warm environment, you may need to take extra precautions to keep the cream cheese frosting from becoming too soft.
Storage: If you're making a cake with cream cheese frosting, it's best to store it in the refrigerator due to the perishable nature of cream cheese. On the other hand, buttercream frosting can usually be stored at room temperature.
Consistency: Cream cheese frosting can be a bit more challenging to work with and achieve a smooth finish compared to buttercream. Make sure the cream cheese and butter are at room temperature before making the frosting and consider sifting the powdered sugar to avoid lumps.
Ultimately, whether you use cream cheese frosting or buttercream frosting comes down to personal preference and the specific cake you're making. If you want a tangy, creamy flavor, cream cheese frosting can be a delicious option, especially for cakes like carrot cake or red velvet cake. For a classic, sweet, and buttery flavor, stick with buttercream. You can also get creative and mix the two frostings or use them together in different layers to achieve a balance of flavors and textures.