We have our design squad member back today showing you how to make a sprinkle fault line cake using some of our modern Christmas sprinkles. This is one of our favorite cake trends! Let’s get started!
Hi everyone! Niki here from Cake by Niki again. I am bringing you another tutorial to try out on your next cake to step up your decorating game! This is a step-by-step guide on how to create your own sprinkle fault line cakes.

This fun cake decorating technique has been around for a number of months now. This style is so versatile. You can use a smooth comb like i did below or even a patterned one to add a little more depth to your design.
There are even a few that have done a vertical fault line in their cake! It’s always fun seeing everyone interpretation on varying decorating styles.
I thought a fun modern Christmas cake would be fun for this time of year. I chose some modern sprinkles for a tweak to the traditional red and green you usually see during Christmas. They were the perfect addition to the frosting colors. Ok, here we go!

How To Make A Sprinkle Fault Line Cake
Gather Cake Decorating Tools
To complete this modern cake decorating look, you’ll need a pack of your favorite sprinkles from Sweets & Treats, (I used Berry Bliss for this cake), a piping bag, an icing scraper, a spatula, and a chilled, crumb-coat cake.

For the crumb coat, don’t worry about it being smooth or perfect at all. As you’ll see, I put much more frosting on it to achieve the fault line look.
Place your crumb coat cakes on a stand with an anti slip pad underneath. Don’t learn the hard way and have a splattered cake on the floor!
Additionally, I always pipe some buttercream underneath the cake and on top of the cake board before icing.

Frost Fault Line Icing Base
Start by spreading a thin layer of buttercream along the middle of your crumb coat cake. This layer will be pretty thin compared to the rest so place just enough to cover the middle of the cake all the way around. There’s no reason for this to be extra thick.

This section of the cake will be covered completely so don’t focus on straight lines at all. Smooth this middle layer of frosting with your icing scraper, bench scraper, or any smooth sided comb tall enough for this task. Make sure to hold it vertically for a perfectly smooth sides of the cake.

Frost Alternating Layer
Cut the tip off of a piping bag and fill with alternate color buttercream frosting, green in this case. Generously pipe the buttercream along the border of your smoothed buttercream strip.

Don’t be chintzy with the buttercream in this step. You want to have enough to smooth the sides out with the comb without showing the layer underneath.

Smooth Entire Frosting Layer
Continue this method on the top and move all the way around the cake. This step gives a boundary of sorts to the fault line on the cake.

Fill in with remaining buttercream and smooth the sides. Do not smooth so much that your buttercream starts to blend with your original strip of buttercream. There definitely needs to be an idea of indention from the outside frosting to the center.

Add Sprinkles To Fault Line
After buttercream is smooth, take a damp, clean finger, and place it into the sprinkles so that a few stick at a time. Place it lightly to your buttercream along the fault line to cover the sprinkles as much as you’d like.

There’s no amount listed for the tutorial, you measure that with your heart! đ You can also use tweezers if you prefer. Fill in the top with buttercream and decorate with your favorite border and more sprinkles.

Pipe Border, Add Finishing Touches
I used an alternating color buttercream ribbon for my top. I covered the top with the rest of the sprinkles. A 4oz container is the perfect amount for this decorating style.

I hope this helps you guys complete your own sprinkle fault line cake! Follow me at @cakebyniki for lots of fun desserts and other decorating ideas!
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Follow along with our friend, Niki on her Instagram page for all of her gorgeous creations. Stay tuned for more decorating methods coming up soon!
Other Fault Line Ideas
There are so many different tweaks you can do to this decorating method. Single color fault or even a patterned fault like Niki did here for July 4th.
What is a fault line cake anyway? As the name implies, it’s a cake that has an exposed area showing a different color, pattern, or even dessert layer underneath an outside layer of cake icing.
Whether it’s vertical, horizontal, or random in nature, the exposed area is such a fun part of the cake to design around. Browse the Fault Line Cakes section on our Pinterest page for more ideas!
Change up the sprinkles and and colors for the perfect holiday dessert. Not sure how many sprinkles you need? Check out our comprehensive overview for different amounts of coverage!
Have a little more fun with this by:
- using different colors in the layers
- changing up the top and bottom frosting colors
- making gold painted fault line borders
- painting the edges of the fault line with coordinating food paint
Most fun of all, this would be perfect pinata cakes by adding sprinkles to the center!
This design technique is so versatile for holidays, birthday parties, and every celebration in between. What a fun birthday cake this would make with confetti icing in the center!
Whatever combination you decide, we can’t wait to see the end result! Feel free to tag us! #SweetsSquad
Love this sprinkle fault line cake tutorial? Check out these others!
- Chocolate Drip Tutorial
- Galaxy Swirl Cupcakes
- Chocolate Pine Cones
- Tree Stump Tutorial
- Traybakes Tutorial