Chocolate Peanut Butter Wonder Cake

Oh. My. Word.  Let me just tell you that this cake is amazing... intensely rich, chocolatey, dense cake layers covered in light and creamy peanut butter frosting and then smothered in smooth, glossy chocolate/peanut butter ganache.  As I think I've said before, I don't usually attempt things that need to look perfect, because I'd rather have the flavors be spot on and not necessarily the presentation.  But this cake is both- the flavors are incredible and it's approachably fancy in appearance.  Even if the frosting isn't perfect on the top, the ganache will easily cover it up and looks neat as it drips over the edges.  I used an icing comb (which you can get at a hardware store for around $1.00- I believe it might be used for cement?) to make ridges along the sides, and I think it all came together very nicely.


I saw this recipe on Smitten Kitchen's site, which is where I find a good amount of my favorite recipes.  I changed it up a bit by making a 2-layer cake instead of a 3-layer one.  This was originally because I thought the layers looked like they would be too thin to do 3 because I was using 9" cake pans instead of 8" ones.  I have now gotten a couple more 8" cake pans that I like because they have straight sides.  My 9" pans unfortunately are slightly angled, which makes it difficult to make straight layer cakes with them.  Here are the 8" pans that I have and like, which I bought off of Amazon.com.


I absolutely love this chocolate cake recipe.  The sour cream makes it moist and dense, and someone even compared it to cheesecake.  I have a few different ideas going with this cake as a base, including a dulce de leche filling and salted caramel buttercream.  Interested, anyone?


Then the frosting is out of this world.  The combination of cream cheese and peanut butter creates a slight tanginess that keeps it from being overly sweet, and complements the cake very nicely.  Make sure you beat it for a while until it's nice and fluffy.  The ingredients should be room temperature.  My favorite way to get cream cheese to room temp without letting it sit on the counter forever is to put the sealed foil package in a bowl of warm water for about 5 minutes.  It works like a dream!

The ganache that goes on top is fairly straightforward.  You melt chocolate chips, peanut butter and light corn syrup in the top of a double boiler and then whisk in half-and-half until it's smooth at the end.  Now this is not the way I learned to make ganache, which is to place the chocolate, peanut butter, and corn syrup in a stand mixer bowl, heat the cream to nearly a boil and then pour it over the chocolate and mix it for 10 minutes until everything is melted and glossy.  I think I will try it this way next time, as it's easier for the chocolate to burn on the stovetop than it is for the cream to burn.  If I try it, I'll let you know how that goes.


Since making this cake, I made a triple-layer red velvet cake with cream cheese frosting and local strawberries between each layer.  I had a little bit of trouble with it trying to imitate the Leaning Tower of Pisa, and so I'm wondering if anyone has tips on making 3-layer cakes more stable?  One thought I had for next time is to put down the first two layers and then let those set up in the refrigerator before adding the top layer, and then letting that one set before frosting the outside.  Feel free to comment if you have any suggestions, but for now I guess I will stick with 2-layer cakes.

Here comes the recipe...

Chocolate-Peanut Butter Wonder Cake

Yield: 1 - 8" triple-layer cake or 9" 2-layer cake

Recipe adapted from Smitten Kitchen

2 cups all-purpose flour

2 1/2 cups sugar

3/4 cup unsweetened cocoa powder, preferably Dutch process

2 teaspoons baking soda

1 teaspoon salt

1 cup neutral vegetable oil (ie. canola)

1 cup sour cream

1 1/2 cups water

2 tablespoons distilled white vinegar

1 teaspoon vanilla extract

2 eggs

1. Preheat the oven to 350 degrees F. Spray the bottoms and sides of three 8-inch round cake pans or two 9-inch round ones. Line the bottom of each pan with a round of parchment and spray the parchment as well.

2. Sift the flour, sugar, cocoa powder, baking soda, and salt into a large bowl. Whisk to combine them well. Add the oil and sour cream and whisk to blend. Gradually beat in the water. Blend in the vinegar and vanilla. Whisk in the eggs and beat until well blended. Scrape down the sides of the bowl and be sure the batter is well mixed. Divide among the 3 prepared cake pans.

3. Bake for 35 to 40 minutes, or until a cake tester or wooden toothpick inserted in the center comes out almost clean. Let cool in the pans for about 20 minutes. Invert onto wire racks, carefully peel off the paper liners, and let cool completely. Freeze the layers, wrapped in plastic wrap, for at least 30 minutes before attempting to frost.

4. To frost the cake, place one layer, flat side up, on a cake stand or large serving plate. Spread 2/3 cup of the Peanut Butter Frosting evenly over the top. Repeat with the next layer. Place the last layer on top and frost the top and sides of the cake with the remaining frosting. (Note: Making a crumb coat of frosting–a thin layer that binds the dark crumbs to the cake so they don’t show up in the final outer frosting layer–is a great idea for this cake, or any with a dark cake and lighter-colored frosting. Once you “mask” your cake, let it chill for 15 to 30 minutes until firm, then use the remainder of the frosting to create a smooth final coating. Once the cake is fully frosted, it helps to chill it again and let it firm up. The cooler and more set the peanut butter frosting is, the better drip effect you’ll get from the Chocolate-Peanut Butter Glaze.)

5. To decorate with the Chocolate–Peanut Butter Glaze, put the cake plate on a large baking sheet to catch any drips. Simply pour the glaze over the top of the cake, and using an offset spatula, spread it evenly over the top just to the edges so that it runs down the sides of the cake in long drips. Refrigerate, uncovered, for at least 30 minutes to allow the glaze and frosting to set completely. Remove about 1 hour before serving.

Peanut Butter Frosting

Makes about 5 cups

10 ounces cream cheese, at room temperature

1 stick (4 ounces) unsalted butter, at room temperature

5 cups confectioners’ sugar, sifted

2/3 cup smooth peanut butter, preferably a commercial brand (because oil doesn’t separate out)

1. In a large bowl with an electric mixer, beat the cream cheese and butter until light and fluffy. Gradually add the confectioners’ sugar 1 cup at a time, mixing thoroughly after each addition and scraping down the sides of the bowl often. Continue to beat on medium speed until light and fluffy, 3 to 4 minutes.

2. Add the peanut butter and beat until thoroughly blended.

Chocolate-Peanut Butter Glaze

Makes about 1 1/2 cups

8 ounces semisweet chocolate, coarsely chopped

3 tablespoons smooth peanut butter

2 tablespoons light corn syrup

1/2 cup half-and-half

1. In the top of a double boiler or in a bowl set over simmering water, combine the chocolate, peanut butter, and corn syrup. Cook, whisking often, until the chocolate is melted and the mixture is smooth.

2. Remove from the heat and whisk in the half-and-half, beating until smooth. Use while still warm.