Kit Kat and M&M Chocolate Cake with Peanut Butter Frosting

Kit Kat and M&M chocolate cake with peanut butter frosting is as fun to make as it is to eat. This impressive layered chocolate cake is ideal for birthdays, celebrations, or any time you want a show-stopping dessert. A moist chocolate base, silky peanut butter frosting, a fence of Kit Kat bars around the sides and a generous crown of peanut-butter M&M’s make this cake both playful and indulgent.

The combination of textures and flavors — tender chocolate layers, rich peanut butter buttercream and crunchy candy — is a guaranteed crowd-pleaser. The decoration is simple to assemble but delivers a high-impact result: line the cake with Kit Kat bars, tie a ribbon around them for a neat finish, and fill the top with M&M’s. It’s a great option if you want a festive cake without complicated piping or advanced decorating skills.

I chose this cake for a child’s birthday because the colorful topping and candy border always get excited reactions. While you can use any reliable chocolate cake recipe for the layers, this version calls for a classic moist chocolate batter that bakes easily in round pans. The peanut butter frosting is straightforward to make in a stand or hand mixer, and it pairs beautifully with the chocolate layers.

If you’re planning this for a party, you can prepare the cake layers a day ahead and refrigerate them wrapped tightly. Assemble and decorate on the day of the event for the best presentation. For guests who prefer no peanuts, this cake strategy works well with other frostings too — for example, a chocolate buttercream or a vanilla cream cheese frosting — but the peanut butter-chocolate contrast is what makes this version special.

This recipe scales nicely and is forgiving: the batter can be thin and still produce tender layers, and the peanut butter frosting can be adjusted for consistency with a splash of milk or water as needed. Whether you are an experienced baker or making a celebratory cake for the first time, the steps are clear, the result looks festive, and the taste is universally appealing. Enjoy crafting and sharing this colorful Kit Kat and M&M chocolate cake.

KIT KAT and M&M Chocolate Cake With Peanut Butter Frosting

Prep time: 15 mins

Cook time: 30 mins

Total time: 45 mins

A moist chocolate layer cake filled and frosted with peanut butter buttercream, surrounded by Kit Kat bars and crowned with peanut-butter M&M’s. Perfect for birthdays and celebrations.

Ingredients

For the cake:
2 cups sugar
1¾ cups all-purpose flour
¾ cup unsweetened cocoa powder
2 eggs
1½ teaspoons baking powder
1½ teaspoons baking soda
½ teaspoon salt
1 cup buttermilk
½ cup canola or vegetable oil
2 teaspoons vanilla extract
1 cup boiling water
For the peanut butter frosting:
2 cups salted butter, room temperature
1¼ cups peanut butter
9 cups powdered sugar
1/3 cup milk or water, plus more as needed
1 cup peanut butter M&M’s
For the decorations:
10–11 Kit Kat candy bars
2 (19.20 ounce) bags peanut butter M&M’s

Instructions

To make the cake

Preheat the oven to 350°F (175°C). Grease and flour three 8-inch round baking pans.
In a large bowl, whisk together the sugar, flour, cocoa powder, baking powder, baking soda and salt.
Add the eggs, buttermilk, oil and vanilla. Beat on medium speed for 2–3 minutes until combined.
Stir in the boiling water. The batter will be thin — that’s normal.
Divide the batter evenly among the prepared pans. Bake 25–30 minutes, or until a toothpick inserted in the center comes out clean.
Cool the pans for 5 minutes, then remove the cakes to a wire rack and cool completely.

To make the peanut butter frosting

In a large bowl, beat the butter and peanut butter together until smooth and creamy.
Gradually add half of the powdered sugar and mix until smooth.
Add half of the milk or water and beat until combined.
Add the remaining powdered sugar and mix well. Adjust the consistency with additional milk or water, a tablespoon at a time, until the frosting is spreadable but holds shape.
Fold in about 1 cup of peanut butter M&M’s if you like some candy pieces in the frosting layers.

Assembly

Place one cake layer on a serving plate and spread about 1 cup of frosting evenly over the top.
Sprinkle roughly ½ cup peanut butter M&M’s onto the frosting and gently press them in.
Top with the second layer and repeat with another cup of frosting and the remaining M&M’s.
Add the final cake layer and frost the top and sides of the cake smoothly.
Unwrap the Kit Kat bars and stand them vertically around the sides of the cake, fitting them tightly together to form a neat fence.
Tie a ribbon around the cake to secure the Kit Kat bars and give a polished look.
Pile the remaining M&M’s on top of the cake. Leave about 1½ inches of vertical space above the cake edge so the candies sit comfortably.
Serve the cake at room temperature for the best texture and flavor.