How to Make a Fault Line Cake

The trend of fault line cakes has really exploded into the cake world in 2019! If you’re not familiar, this new trend is really just a way of frosting cakes where you have a ring of decoration, then you frost the rest of the cake without covering up that ring.

The actual “fault line” can be decorated with anything imaginable. Sprinkles, buttercream flowers, and fruit are just a few of the options I’e seen. For my fault line cake, I chose to decorate the fault with an abstract buttercream pattern to makes things a bit easier.

Although the entire process of making a fault line cake is relatively easy, I did pick up a few tips along the way that will make it much easier for you! Read on on for my tips and a full set of instructions, or watch my tutorial video!

Tips for Making A Fault Line Cake:

1. Opt for a taller cake. This tip isn’t absolutely mandatory, but it does make things easier. When I set out to make a fault line cake I started with my usual 6 inch/3 layer cake. I quickly realized, however, that this didn’t give me much room for my fault line. Instead, I added another three layers! So if you have the option, using a taller cake will give you a lot more vertical space in which to create your fault line.
2. Make you fault design bigger than you think it needs to be. It’s not really obvious at first, but when you go to smooth out your final coat of frosting, much of that frosting will get pushed over the edges of your fault line. Make the design larger than you think it needs to be, that way you won’t end up covering too much of it with your final frosting!
3. Make sure your cake is well chilled between frosting the center ring and frosting the rest of the cake. As with any sort of buttercream design, a tiny bump can really mess things up! After you create your fault line design, let it chill in the fridge until everything is completely firm. This way, if you bump into the center while you frost the rest of the cake, it won’t get messed up.
4. Make sure your final coat of frosting is thick enough to stand out from the fault design. Part of what makes fault line cakes look so cool is the contrasting depth between the fault line and the outer frosting. Use a very thick coat of frosting so that after smoothing it still stands out from the center design.

How to Make a Fault Line Cake Step-by-Step

1. Prepare your cake. Have your cake stacked, crumb coated and chilled before you start your design. You can use any type of buttercream to make this design.
2. If you like, use a knife to trace out a rough guide of where you want to the fault line to be.
3. Decorate the fault line with your design of choice. I made a simple abstract pattern by dabbing small blobs of buttercream with the back of a spoon. If you’d like to attach sprinkles, fruit, etc., frost the center with a thin coat of frosting to give your decorations something to stick to.
4. Chill the cake until the center design in completely firm.
5. Frost the rest of the cake with a very thick coat of buttercream. Apply the frosting only just to the edges of your center design. Because you need to avoid the middle, I found it easier to use a piping bag for this step.
6. Using an offset spatula or a cake scraper, smooth out the final coat of frosting. As you smooth, the frosting will get pushed over the edges of your center design, creating the fault line effect.
7. Chill the cake again, until the outer frosting is firm.
8. At this point, your cake can be finished, or you can choose to add more decorations. Many people choose to highlight the fault line edges by painting them with a contrasting color. I piped small stars along the edges of my fault line with a number 16 star tip.