A new version of my Chocolate Peanut Butter Cake made with a doctored cake mix and filled with a delicious, easy-to-make peanut butter mousse, and frosted with rich fudge icing.
I can never quite decide how I want to make this Chocolate Peanut Butter Cake. As there are no written laws, it make baking all the more fun. It’s very hard to go wrong with the classic peanut butter and chocolate combo, am I right?
Obviously, this cake is all about the peanut butter and chocolate. It’s that simple. And there are so many ways to make it even more sinful – add ganache or fudge frosting, chop up some peanut butter cups for the top, or put some nestled in the mousse between each cake layer… Every time I make it, the components are generally the same, but I shake it up a little. Never exactly the same twice.
Both Homemade and Cake Mixes Work Great!
This year, because it was my dear friend’s cake I was making, I wanted to make sure I didn’t mess it up. (When I’m pregnant, my baking is very unpredictable.) I had an idea I wanted to try. I wanted to doctor a cake mix because I knew if all else failed, the cake would at least be okay. (Yes, I use cake mixes occasionally.) It worked out really, really well. It tasted great. I ended up topping the cake with both chocolate shavings and chopped peanut butter cups. PB + chocolate overload!
If you prefer to make a homemade cake (which I think is ultimately the best option), then this cake is a really perfect one from America’s Test Kitchen. I also really love Hershey’s Perfectly Chocolate Cake too. Either one of those turn out perfectly. Every single time.
The Mousse Filling Makes This Chocolate Peanut Butter Cake
My peanut butter mousse isn’t a true mousse made with eggs and such. I cut a few corners and use cream cheese. The flavor is exquisite, I promise. The slight tang of the cream cheese works well with the slight sweetness and the saltiness of the peanut butter. The whipped cream lightens the mixture. See below for how-to photos and a few extra tips.
I don’t use natural peanut butter when making desserts. I like natural peanut butter much better than the other kinds, but it can make desserts too oily. Those extra additives and stablizers help a lot. I really like Jif or Skippy the best, but a store brand works well too. Save the natural peanut butter for eating by the spoonful, dipping apples into, and drippy, delicious PB&J sandwiches. :)
- For cake:
- 1 German Chocolate Cake mix (Duncan Hines is the one I used)
- 3 heaping Tablespoons cocoa powder
- 1 stick butter, melted
- 3 large eggs
- 1¼ cups milk
- For Peanut Butter Mousse:
- 2 cups peanut butter (not natural)
- 8 ounces cream cheese
- 1 cup powdered sugar
- 1 teaspoon pure vanilla extract
- 1 cup heavy cream, chilled
- For Fudge Icing:
- ½ cup butter
- 4 heaping Tablespoons cocoa powder
- 2-3 cups powdered sugar (may not need all of it)
- ½ cup heavy cream
- Pinch salt
- For garnish:
- Chopped peanut butter cups or chocolate shavings
- For cake: Preheat oven to suggested 350°F. Grease two 8- or 9-inch round cake pans; dust the inside with cocoa powder. Set aside.
- Place cake mix, cocoa powder, melted butter, eggs, and milk in a large mixing bowl. Beat with electric mixer on low speed for 30-60 seconds to combine the ingredients, then beat for -23 minutes on medium speed. Scrape down sides of bowl as needed.
- Divide batter between the cake pans. For two 8-inch cake pans, bake for 26–31 min; for two 9-inch pans, bake 23–28 min.
- Cool cakes for about 10 minutes in the pans. Run a thin knife around the edges to loosen and transfer the cakes to a wire rack to finish cooling. Refrigerate or freeze cakes, if desired, to make assembly easier.
- For Peanut Butter Mousse: In a medium mixing bowl, beat peanut butter and cream cheese with an electric mixer until creamy. Add the powdered sugar and vanilla. Beat until combined. The mixture will be thick.
- Clean the beaters and place chilled heavy heavy cream in a clean mixing bowl and beat until soft peaks form.
- Fold the whipped cream into the peanut butter in two additions. (The purpose of the first addition of cream is to lighten the mousse a bit so it doesn't deflate.)
- Cover bowl and chill peanut butter mousse until ready to assemble the cake.
- For Fudge Icing: Place the butter in a medium saucepan. Melt over medium heat. Remove from heat and stir in cocoa powder.
- Using an electric mixer, beat in part of the powdered sugar and a few tablespoons of the heavy cream. Add more powdered sugar and cream until icing is at a spreadable consistency. Cover and set aside until ready to assemble cake. Can be made in advance and stored in refrigerator. Let come to room temperature and beat frosting again until spreadable.
- To assemble the cake: If desired, split the the two cake layers horizontally, or leave as-is. (For this cake, there were two 8" rounds that I split into half horizontally to create 4 layers of cake and three layers of filling. The directions below reflect that.)
- Pipe or spread ¼ of the PB mousse on the bottom layer. Top with next cake layer. Repeat with mousse and cake layers 2 more times.
- Spread top and sides with Fudge Icing. (There may be extra.)
- Pipe the remaining peanut butter mouse onto the top of the cake in a decorative pattern, if desired.
- Garnish the cake with chopped peanut butter cups and/or chocolate shavings, if desired. Enjoy it with a scoop of vanilla ice cream, or a huge glass of milk.
Using an electric mixer, beat the peanut butter and cream cheese. Add the powdered sugar and vanilla. Beat until combined.
It will be thick! Clean the beaters and beat the heavy cream in a clean bowl until soft peaks form.
Fold the whipped cream into the peanut butter in two additions. (The purpose of the first addition of cream is to lighten the mousse a bit. You don’t want it to deflate!)
Chill until ready to assemble the cake.
The peanut butter mousse is the perfect consistency for piping and it holds its shape really well. I like to place all of the mouse into a piping bag. It’s the easiest way to distribute it between the layers and to decorate the top. Aren’t those whorls gorgeous?
The cake looks more complete with a sprinkle of chocolate shavings and some chopped peanut butter cups.