A Kit Kat Cake is a fun and colorful cake that is perfect for a birthday or any special occasion. The secret to a great Kit Kat Cake is covering the cake with a thick chocolate frosting that will hold the Kat Kats onto the side of the cake without any ribbons for support.
This Kit Kat Cake, or sometimes called Hot Tub Cake, takes a traditional chocolate cake and dresses it up by lining it with Kit Kats and then topping it off with all kinds of colorful candies.
Often times, these cakes are topped with only M&Ms candies and that looks so cute!
If using only M&Ms on the top, you will need two large bags of candy.
While that looks perfectly cute, my birthday girl loves fruity candies like gummy bears and Skittles so I definitely want to make sure those were on her birthday cake.
Disclosure – I may get a small commission for purchases made through affiliate links in this post.
Key to Success #1 – Make Homemade Chocolate Buttercream
Who knew that you could cake a basic chocolate cake mix into something as fabulous as this Kat Kat Cake?
Adding a homemade buttercream frosting to a boxed cake is a great way to make your cake taste way better.
Nobody will know it’s semi-homemade.
The thick chocolate buttercream will help the Kit Kat bars stand up without falling off the cake before you can serve it at your party.
You can use the recipe for our Perfect Chocolate Buttercream Frosting to make the perfect thick frosting for this cake.
It holds up well and we have zero issues with the Kit Kats sliding around when we use this buttercream frosting recipe.
With this type of buttercream frosting, you really do not need to add a ribbon around the Kit Kats for support, but you can add one if you like the look of it!
Key to Success #2 – Make Sure the Cake is Level
Another important piece of advice is to make sure the top of your cake is level before adding the Kit Kats.
This is not so much because the Kat Kats won’t stick, but more so that the candies on the top will have a solid surface to rest upon.
If the cake is domed on the top, then the candy on the top of the cake may press on the Kit Kats and make them fall down.
You can use a sharp serrated knife to gently saw through the cake right below where the dome of the cake begins to rise up.
Work slowly all the way around the cake until the domed top can be removed.
Keep in mind that you can always remove more cake from the top if it’s not perfect the first time.
When adding the frosting, make sure to keep it level as well.
The frosting around the edges of the cake should be the same thickness as the frosting right in the middle of the cake.
Key to Success #3 – Refrigerate After Adding Kit Kats
The Kit Kats are easy to place around the perimeter of the chocolate cake.
Here are some things to keep in mind:
- Add the Kit Kats immediately after you add the chocolate buttercream frosting. Otherwise, the frosting could form a crust and it will be harder to adhere the candy bars to the cake.
- Make sure each Kit Kat stick is separated before starting. This will make the final result much smoother and will aid in cutting the cake.
- Place the Kit Kat Cake in the refrigerator after adding the Kit Kats and before adding the candy on the top.
Refrigerating the cake after adding the candy bars will speed up the setting process for the frosting.
The frosting will form a crust that will act as a glue for the Kit Kats.
After the cake has set for at least 30 minutes, you can remove it from the refrigerator and allow it to come to room temperature.
I add the candy to the top as soon as I bring the cake out of the refrigerator.
Consider grabbing some extra-long candles if you are using this as a birthday cake.
You will want to make sure the candles are long enough to reach all the way down through the candy to the cake so that they will stay in place.
The candles in the photo are 5.5 inches tall and they are linked below if you need them.
Save this Kit Kat Cake recipe to your favorite Birthday Cake board or your Chocolate Desserts board.
For the Cake
- 1 box (15 oz) Devil's Food cake mix
- 1 cup water
- 4 eggs
- 1/3 cup vegetable oil
For the Frosting
- 1 recipe Chocolate Buttercream Frosting *See Link Below for Recipe
For the Decorations
- 12 regular Kit Kat candy bars
- 1 bag M&M's candies
- 1 box Whoppers
- 1 bag Gummy Bears
- 1 bag Skittles
- 1 bag Mini M&Ms
- or any other colorful candies
- Preheat the oven to 350 degrees F. Grease two identical 9-inch round cake pans.
- In a large mixing bowl, combine Devil's Food cake mix, water, eggs, and vegetable oil. Mix on medium speed 2 minutes until combined.
- Divide the batter between two cake pans.
- Bake cakes for 24-30 minutes until a toothpick inserted into the center of the cake comes out clean. Cool the cake layers completely.
- Use a stand mixer to whip up Chocolate Buttercream Frosting.
- When the cake layers are cool, level the cakes if needed then place one layer in the middle of the serving plate.
- Cover the top of the chocolate cake with a layer of chocolate buttercream frosting,
- Add the second layer then spread chocolate frosting all over the sides and top of the cake with a knife. Make sure the top of the cake and frosting is level.
- Separate the Kit Kat bars into individual sticks.
- Place the Kit Kat sticks side-by-side all the way around the cake, pressing them gently into the chocolate frosting. Make sure each Kit Kat is right up next to the one beside it.
- Place the cake into the refrigerator to firm up for at least 30 minutes.
- Remove the cake from the refrigerator and add the candies and decorations to the top.
- You can substitute any cake mix flavor for this Kit Kat cake recipe. If you'd prefer, you can bake the cake according to the package directions instead of using the extra egg that is called for in this recipe.
- Use this link for the Buttercream Frosting Recipe.
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Nutrition Information:Yield: 18 Serving Size: 1
Amount Per Serving: Calories: 407Total Fat: 18gSaturated Fat: 8gTrans Fat: 0gUnsaturated Fat: 7gCholesterol: 52mgSodium: 311mgCarbohydrates: 56gFiber: 2gSugar: 37gProtein: 7g
Nutrition Information Provided For Educational and Informational Purposes Only.