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Spooky fault line Halloween cake decorated with sprinkles, candy monster eyes and bold buttercream colors. Create this show stopping cake for your Halloween party or just for some spooky fun!
Halloween is my favorite holiday. It’s the one holiday you don’t have to travel, cook a huge meal and plus there’s candy. I love making Halloween treats like these candy corn cupcakes and this spiderweb cake. This year, I wanted to make a Halloween cake using the super trendy fault line technique with a spooky twist.
Fault Line Cake
My first fault line cake was a simple Swiss meringue buttercream with sprinkles. For this cake, I used my American buttercream frosting and a 6″ inch vanilla cake (recipe below). This technique looks challenging but it’s not hard to make! Here are the steps to making the perfect fault line Halloween cake.
STEP 1: ADD A THIN LAYER OF FROSTING AROUND THE MIDDLE OF THE CAKE
After you have crumb coated the cake and chilled the cake, add a thin layer of frosting around the middle of the cake. This is where your sprinkles will go so make sure you have the width that you desire.
STEP 2: ADD SPRINKLES TO THE LAYER OF FROSTING
Put a cookie sheet underneath the cake to catch all the excess sprinkles. Then, gently add sprinkles to the middle layer of frosting all around the cake. Be gentle when putting on the sprinkles so you don’t dent the cake.
For this Halloween cake, I used Halloween sprinkles similar to these Hocus Pocus sprinkles and monster candy eyes.
STEP 3: ADD FROSTING TO THE TOP AND BOTTOM OF THE SPRINKLES
Using your offset spatula, add frosting to the top and bottom of the sprinkles. Don’t worry about it being perfect. This is the beauty of the fault line cakes. Allow the natural flow of frosting to go up and down. This will create a more natural “fault line” in your cake. Be sure to add a equal layer of frosting around the cake.
STEP 4: ADD FROSTING TO THE TOP OF THE CAKE
Don’t forget to add a layer of frosting to the top of the cake!
STEP 5: SMOOTH OUT THE FROSTING
Using a bench scraper, slowly scrape the frosting to remove the excess frosting. You can start by scraping down the sides of the cake. Then, scrape and smooth the top of the cake. Be sure to clean your bench scraper in between each scrape. Continue scraping and removing frosting until you have smooth layer of frosting all around the cake.
STEP 6: ADD DECORATIONS AND MORE SPRINKLES
Finish the cake with any final decorations. I added a cake border around the top and of course, more sprinkles!

- Fault Line Cake Tutorial
- Spooky Spiderweb Cake
- Candy Corn Cupcakes
- White Cake from Scratch
- American Style Buttercream
Vanilla Cake
Ingredients
- 2 cups cake flour (280 g)
- 1 teaspoon salt
- 2 1/2 teaspoon baking powder
- 1/4 teaspoon baking soda
- 4 egg whites
- 2 sticks of butter (226 g) - room temperature
- 1 1/4 cups sugar (280 g)
- 2 tsp vanilla
- 1 cup milk room temperature
- 1/2 cup sour cream (125 g) room temperature
Buttercream Frosting
- 1 cup butter (227 g) room temperature
- 1/2 cup shortening (Crisco) (100 g)
- 6 cups sifted powered sugar (750 g)
- 1/4 cup milk
- 1 tablespoon vanilla
Instructions
- Preheat oven to 350°F/177°C. Butter and flour three 6 inch cake tins and line with parchment paper.
- Combine all the dry ingredients (cake flour, salt, baking powder and baking soda) in a medium bowl, whisk together and set aside.
- In a small bowl, mix the milk, sour cream and vanilla together. Set aside.
- Using a handheld or stand mixer with the paddle attachment, beat the butter and sugar on medium speed (4) for about 3 minutes until smooth and creamy. Scrape down the sides of the bowl with a spatula.
- Whisk the egg whites together with a fork and slowly drizzle the egg whites into the mixture. Keep it on low speed (2) until all the egg whites are added and then increase the speed to high (8) for about 1-2 minutes until combined. (May look curdled but it will smooth out as you beat). Scrape down the sides of the bowl.
- On low speed, add half of the dry ingredients and mix until barely incorporated. Then add half of the milk mixture and mix for a few seconds. Then add the remaining dry ingredients mixing for a few seconds and then add the remaining milk mixture. Turn off the mixer and mix it by hand with a rubber spatula to make sure the batter is combined. Do not overmix the batter.
- Pour the batter evenly into the pans (about a third of the way full). Bake for about 30-35 minutes until the cakes are cooked. Insert a toothpick into the center of the cake, if it comes out clean then it's done.
- Allow cakes to cool completely (15-20 minutes) and then gently remove the cakes from the pans and allow them to rest on a wire rack.
Make the Buttercream Frosting
- In a stand mixer with the paddle attachment, beat butter and shortening on medium speed until smooth and creamy (2-3 minutes). Add half of the powdered sugar and beat of low speed for 30 seconds. Add a 1/4 cup of the milk and mix on low. Add the remaining powdered sugar. Add vanilla. Mix on low for 30 seconds and gradually increase the speed to high and beat for 2 minutes. If it is too thin, add more powdered sugar. If is it too thick, add more milk.
Assemble
- Add a layer of buttercream between each cake layer. Cover the cake with a thin layer of buttercream. Use an offset spatula and a bench scraper to smooth the frosting. Put the cake in the fridge for at least 10 minutes and then apply another thin layer of frosting to the sides and top of the cake. If desired, add food coloring to a small amount of frosting and pipe buttercream flowers on the sides.
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