Chocolate Peanut Butter Cup Cake
Chocolate cake, peanut butter frosting, chocolate ganache, peanut butter cups. This Peanut Butter Cup Cake is a chocolate and peanut butter lover’s dream.
Today is my birthday. I’m not really one for cake, so instead, I made myself some mint chocolate chip ice cream after noticing that my mint was growing out of control.
It’s funny; I had no problems at all with turning 30, but for some reason, 31 just seems so much older. No, it’s not logical, and yes, I know 31 isn’t actually old.
Perhaps it’s because my lab is very graduate student heavy, and I spend most of my time with 23-year-olds. Maybe it’s because so many of my friends had children this year and it’s hard for me to grasp that yes, we actually ARE old enough to have children.
Either way, no matter how old I’m feeling, I always get to remain a year younger than my husband and his friends.
It only seemed appropriate that I post a birthday cake on my birthday, even if it’s not for me – this was initially made for two of my husband’s closest friends, on account of their birthdays, and was an enormous hit.
I’m not one for chocolate cake, but the peanut butter frosting? Just give me a big bowl and a spoon, please.
The chocolate cake is light and fluffy, surrounded by thick layers of rich peanut butter frosting. Warm chocolate ganache is then poured on top, dripping down over the sides.
Think it can’t get any better? Go ahead and cover the top with chopped peanut butter cups. Oh, did I forget to mention that there are more peanut butter cups between each layer of cake? Yeah, that.
This peanut butter cup cake is truly a chocolate and peanut butter lover’s dream come true.
This is, without a doubt, the most requested cake that I have made. I’ve made it for birthdays. I’ve made it for anniversaries. I made it for our neighborhood rotating dinner party, which led to a neighbor asking if I’d make it for her son’s first birthday party.
I’ve made it so much that I’m purposely taking a break and not making it for a while – there are other cake options out there, people!
How about a banana nutella cake? Or carrot cake? Maybe an oreo cake? Flourless chocolate cake? Chocolate ganache bundt cake? Or maybe even a candy cake – I haven’t made one of those in a while!
Better yet – ask me to make something I haven’t already posted on my blog, so I have an excuse to create and post a new recipe!
Oh fine, you want another peanut butter cup cake? I can’t say no.

Chocolate Peanut Butter Cup Cake
Chocolate cake, peanut butter frosting, chocolate ganache, peanut butter cups. This Peanut Butter Cup Cake is a chocolate and peanut butter lover’s dream come true.
Ingredients:
For the cake:
- 2 1/2 cups plus 1 tablespoon all-purpose flour
- 3 cups granulated sugar
- 1 cup plus 1 tablespoon cocoa powder
- 1 tablespoon baking soda
- 1 1/2 teaspoon baking powder
- 1 1/2 teaspoon salt
- 3 eggs
- 1 1/2 cups buttermilk
- 1 1/2 cups coffee, hot
- 3/4 cup vegetable oil
- 4 1/2 teaspoons vanilla extract
For the peanut butter frosting:
- 2 cups powdered sugar
- 2 cups creamy peanut butter
- 10 tablespoons unsalted butter, room temperature
- 1 1/2 teaspoons vanilla extract
- 1/2 teaspoon kosher salt
- 2/3 cup heavy cream
For the chocolate ganache:
- 8 ounces dark chocolate, chopped
- 3/4 cup heavy cream
- 30 miniature peanut butter cups, divided
Directions:
- Preheat the oven to 350F. Grease and flour three 8-inch round cake pans.
- Whisk together the eggs, buttermilk, coffee, oil, and vanilla, and set aside.
- Stir together the flour, sugar, cocoa powder, baking soda, baking powder, and salt in the bowl of a mixer. Add the wet ingredients to the dry ingredients and mix until combined, about 2 minutes. The batter will be quite thin.
- Divide the batter evenly among the three pans. Bake for 30 minutes, or until a toothpick inserted into the center of the cake comes out almost clean. Cool the cakes in the pan for 20 minutes, then turn out onto cooling racks to cool completely.
- To prepare the frosting, combine the powdered sugar, peanut butter, butter, vanilla, and salt in an electric mixer fitted with the paddle attachment. Beat on medium-low speed until fluffy. Add the heavy cream and beat on high speed until the frosting is light and smooth.
- To assemble the cake, level the cakes if necessary. Cover the bottom layer of cake with 1 cup of the peanut butter frosting, and sprinkle 10 of the chopped peanut butter cups over the frosting. Top with a second cake layer and cover with another cup of the frosting, followed by another 10 chopped peanut butter cups. Place the final layer on top of the cake, face down, and frost with the remaining peanut butter frosting. Refrigerate the cake for at least 1 hour, until the frosting is set.
- While the cake chills, prepare the chocolate ganache. Place the cream in a small saucepan over medium heat and warm just until it comes to a boil. Place the chopped chocolate in a glass mixing bowl or a 4-cup measuring cup, and pour the cream over the chocolate. Allow this mixture to sit for 2 minutes to melt the chocolate, and then whisk from the center outside until the ganache is smooth. Set aside to cool, whisking occasionally, until the ganache has thickened but is still pourable.
- Slowly pour the chocolate ganache into the center of the cake, allowing it to push itself outward and flow down the sides of the cake. Top with the remaining chopped peanut butter cups. Refrigerate until the ganache is set, at least 30 minutes.
Recipe adapted from Brown Eyed Baker
What an incredible cake that looks like! Love all that ganache, mmm 🙂
Do you know why the coffee has to be hot?
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I just wanted to say thank you for this amazing recipe!!!! I made this cake and seriously I think it is the best cake I have ever eaten! So thank you!
Yay!! I’m so glad you liked it – it’s definitely my husband’s favorite cake, too! Thanks for letting me know how much you liked it; comments like these totally make my day!
This cake was incredible! I wrapped (well) the cake layers and froze them for a week. This was described by almost everyone at the party as the best cake they had ever had. Thanks for the recipe!
I’m so glad everyone liked it, Jessica!! These kind of comments totally make my day. 🙂
I made this cake last week and it was a HUGE hit. It was the first time I’ve made a 3 layer cake and the first time I used my brand new stand mixer for it. It was also 1/3 gone in the first 30 minutes of being set out. Absolutely delicious and so moist! Thank you for this recipe!
Yay! I’m so glad you loved it — comments like this make my day. What a great way to break in your new mixer!
So 2 quick Qs… im not a baker… i try and try… so any tips you can offer to make this fail proof?
How many do you think this would serve? Im thinking about attempting this for my sons 3rd bday… going to decorate with some construction trucks digging in the “mud” & “boulders” lol
Hi Annie! In the recipe I list it as “serves 12” but these are pretty generous adult-sized slices – I’d guess you could get away with at least 20 for kids. I love the idea of turning it into a construction cake – my 2.5 year old son would LOVE that!
Should this cake be refrigerated before and after serving (assuming there is any leftover ?)?
The cake is good for up to 2 days at room temperature; any longer and you’ll want to refrigerate it (up to a week). Enjoy!!
Looks so good! My niece asked me to bake this cake for Thanksgiving. I love baking during the holidays but I need to know if you can freeze the cake?
Absolutely! If you want to make the cake ahead of time, I’d recommend baking the three layers of cake, letting them cool completely, wrapping in plastic wrap, and then putting each layer in a freezer bag and storing them in the freezer for up to 3 months. Thaw overnight at room temperature before frosting. If you want to save pieces of cake after it’s been frosted, cut individual slices of cake and freeze them on a cookie sheet in the freezer. Once full frozen, wrap the individual cut slices of cake in plastic wrap and store in a freezer bag.
Does it matter what kind of coffee??
No! Anything with a strong flavor (like hazelnut) might show up a little in the final version, but dark roast, light roast, etc., does not matter. The coffee just helps bring out a more pronounced chocolate flavor – I just grab whatever coffee K-cup I can find first. 😉
This is the best cake I’ve ever made!!!! I made it for my husband’s birthday and it was soooooo good. It didn’t taste like coffee at all (I was nervous) just extra chocolatey.