It’s been quite some time since I’ve put together a massive layer cake. Part of the reason is that I’ve been pretty busy over the past few months. There was a string of friends and family visiting all summer long followed by a tumultuous and hectic move to a new apartment. The final boxes were unpacked a few weeks ago, so now I finally have time to bake again and the timing really couldn’t be better.
This past weekend was my girlfriend’s birthday and she requested that I make her an extra special cake. Steph’s been thinking about her birthday centerpiece for a while and the request for the cake seemed to change weekly! One week it was a chocolate and peanut butter cake, then it was a Boston Cream Pie (recipe here), then it was a lemon cake, then it was back to the Boston Cream Pie, then it was some mutant amalgamation of all of those put together, and on and on it went.
I let the ideas pour out but finally, as her birthday approached, we sat down and came up with a final plan for the cake. Chocolate and peanut butter were kept in, but we took our inspiration from a Snickers bar to bring caramel to the party too. Chocolate, peanut, and caramel: three bold flavors that not only go together well, but are also strong enough to stand up to each other and not be drowned out.
Having our inspiration, I took it from there and developed this beast of a cake. Three layers of chocolate cake, with a gooey caramel between the layers, covered in a peanut butter frosting, then topped with a dark chocolate ganache dripping down the sides and some shaped peanut brittles and chopped peanuts for decoration. This ended up being one seriously massive, heavy cake, but as tasty as it sounds!
I combined recipes from a handful of sources for this cake. For the chocolate cake itself, I tried a new recipe from a favorite cookbook of mine, Baked Explorations, by the guys behind the Brooklyn-based bakery simply named Baked. Their cake gets its chocolatey flavor by only using cocoa powder, no melted chocolate in there, so make sure you use your best quality Dutch-processed cocoa powder. (Not sure what the difference is between natural and Dutch-processed cocoa powder and which one you have? Check out this great explanation from David Lebovitz.)
The caramel filling recipe was a bit trickier to find. I’ve used a caramel sauce as a filling between layers of an apple cake and it ultimately soaked into the cake, creating a caramel zone but no discrete layer of filling. I was determined to find another caramel filling that would stay where I put it, between the cake layers. After searching all of my cookbooks on the shelf and spending more time than I’d like to admit scouring the web, I still wasn’t satisfied with any of the recipes I found. With my frustration and lackluster search results, I reached out to my mother (and baking mentor) to see if she had any promising caramel recipes. She found one at CakeCentral and after reading through the dozens of comments left by other bakers, I had my caramel filling recipe in hand.
One specification for this cake was that I not use a frosting with a strong butter flavor. To accomplish this and to add a bit of tang to offset the sweetness of the peanut butter, I turned to a Peanut Butter Cream Cheese Frosting from Smitten Kitchen. While there is still some butter in there, the cream cheese and peanut butter mask its flavor. I also increased the peanut butter beyond the original recipe to really make it stand out.
During our conversation about which cake she wanted, we finally figured out that the reason Steph kept coming back to the Boston Cream Pie was the chocolate ganache poured on top. With the addition of this topping on her birthday cake, we were able to merge the chocolate-peanut butter idea with the Boston Cream Pie one. The ganache is just chocolate, butter, and a bit of corn syrup, so make sure you use a high-quality (60-70%) dark chocolate to make that deep chocolate flavor shine.
To add further decoration I make some shaped peanut brittles. I had a handful of fluted metal molds, so I greased them up with a little oil, put a handful of peanuts in each, and then poured caramel over top until the molds were full. Once cooled and carefully unmolded, I was left with beautifully shaped peanut brittles. At the last minute, I decided the cake needed a centerpiece, so I made another batch of caramel and poured it into a star-shaped cookie cutter sitting on top of a parchment paper-lined cookie sheet.
This cake was a large undertaking, but thankfully I was able to make the cakes and caramel filling a day before. This indulgent three-layer cake packs quite a punch and I was able to feed 35 festive friends from this single cake. Needless to say, the cake was a huge hit among the partygoers and, more importantly, with my girlfriend. I think her smiling face says it all.
- 3/4 cup (90 g) Dutch-processed cocoa powder
- 2/3 cup (162 g) sour cream
- 1 1/4 cups hot water
- 2 2/3 cups (373 g) all-purpose flour
- 2 teaspoons baking powder
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 12 tablespoons (171 g) unsalted butter, cut into 1 inch (2 cm) cubes, softened
- 1/2 cup (100 g) vegetable shortening
- 1 1/2 cups (300 g) granulated sugar
- 1 cup (220 g) packed dark brown sugar
- 3 large eggs, at room temperature
- 1 tablespoon vanilla extract
- 8 tablespoons (112 g) butter, cut into 1 inch (2 cm) pieces
- 1 cup (200 g) packed brown sugar
- 1/2 cup (163 g) light corn syrup
- 7-oz (200 g) sweetened condensed milk (save the other half of the can for another purpose)
- 1 tablespoon heavy cream
- 1 teaspoons vanilla extract
- 1/2 teaspoon salt
- 10 oz (283 g) cream cheese, at room temperature
- 8 tablespoons (114 g) unsalted butter, at room temperature
- 5 cups (510 g) confectioner's sugar, sifted
- 1 cup (258 g) smooth peanut butter, preferably a commercial brand so the oil doesn't separate out
- 8 oz. (227 g) good-quality (60-72%) dark chocolate, coarsely chopped
- 12 tablespoons (171 g) unsalted butter, softened and cut into 1/2 inch (1 cm) pieces
- 1 tablespoon light corn syrup
- 8 fluted metal cup molds (about 1 inch (2-3 cm) in diameter)
- 2 tablespoons vegetable oil
- 1/3 cup (50 g) peanuts
- 1/2 cup (100 g) granulated sugar
- 1/2 cup (75 g) chopped peanuts, strained to remove peanut dust
- Preheat the oven to 325 °F (165 °C). Butter three 8" (20 cm) round cake pans, line them with parchment paper, and butter the parchment, Dust the parchment with flour and knock out the excess.
- In a medium bowl, mix the cocoa powder, sour cream, and hot water and set aside to cool.
- In a large bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.
- Using a standing mixer fitted with the paddle attachment, beat the butter and shortening together on medium speed until light and fluffy, about 5 minutes.
- Add the sugars and beat on medium speed until light and fluffy, about 5 more minutes.
- Add the eggs, one at a time, mixing about 10-15 seconds after each addition until each egg is incorporated into the mixture.
- Turn the mixer to low, add the vanilla, and beat until incorporated. Scrape down the sides of the bowl and mix again for 30 seconds.
- Beginning with the dry ingredients, add the dry mixture and the cocoa mixture to the mixer bowl in three alternating parts, ending with the dry.
- Divide the batter evenly among the prepared pans. Use an offset spatula to level the batter.
- Bake the cakes for 35-40 minutes, rotating the pans halfway through the baking time, until a toothpick inserted in the center comes out clean.
- Transfer the pans to a wire rack and cool for 30-45 minutes. Turn the cakes out onto the rack and let them cool completely. Remove the parchment.
- In a heavy saucepan, bring the butter, brown sugar, corn syrup, and sweetened condensed milk to a boil over medium heat, stirring continuously.
- Carefully stir in the heavy cream.
- Attach a candy thermometer to your pan and continue stirring until the caramel reaches the thread stage, 230-235°F (110-113°C).
- Remove from the heat and mix in the vanilla and salt.
- Allow to cool.
- Beat the cream cheese and butter in the bowl of your electric mixer until light and fluffy (about 5 minutes).
- Gradually add the confectioner's sugar, 1 cup at a time, mixing thoroughly and scraping down the sides of the bowl often.
- Continue to beat on medium speed until light and fluffy (3-4 minutes).
- Add the peanut butter and beat until thoroughly blended.
- Store, covered, in the refrigerator if not using immediately.
- Place the chocolate, butter, and corn syrup in the top of a double boiler.
- Using a rubber spatula, stir the mixture until the chocolate and butter are completely melted and smooth.
- Remove the pan from the heat and stir the glaze to release excess heat.
- Transfer to a 2-cup heatproof measuring cup to cool and for easy pouring.
- Pour the vegetable oil into one mold, tilt to mold to coat, then pour out the excess into the next mold and continue as before.
- Place the molds on a sheet of parchment paper on top of a cookie sheet and add a few peanuts into each mold. Set aside.
- Spread the sugar in a thin layer in a light-bottomed pan over medium heat. Don't walk away during this process as the caramel starts to darken suddenly and then proceeds rapidly.
- Wait until the edges of the sugar start to melt, then gently stir the sugar to help it brown evenly.
- Once the caramel reaches a reddish-brown color (similar to a penny), take it off the heat and immediately pour it into the prepared molds until full.
- Let the brittles cool, then carefully unmold them and store in an airtight container (at room temperature) until ready to use.
- Place one cake layer on a serving platter. Trim the top to create a flat surface if necessary.
- Fill a pastry bag with a medium round tip with some of the peanut butter frosting. Pipe a ring of frosting around the rim of the top of the cake.
- Fill in the circle of frosting with the caramel. Caramel that has reached the thread stage should be pourable, but if you have cooked it too long, it may require you to use your hands to help mold the caramel into a layer on top of the cake. This caramel layer should be 1/8 - 1/4 inch (0.25 - 0.5 cm) thick.
- Add the next layer of cake. Trim, frost a ring of frosting, and top with a layer of caramel as before.
- Add the third layer of cake.
- Spread a very thin layer of frosting over the sides and top of cake (the crumb coat) and put it in the refrigerator for about 15 minutes to firm up.
- Spread the sides and top of the cake with the remaining frosting. Refrigerate for 15 minutes to firm up.
- Slowly pour about 3/4 cup of the glaze over the cake. Use a small offset spatula to smooth it out to the edges (without going down the sides). Place the cake in the refrigerator for 5 minutes to set the glaze.
- Remove from the refrigerator and slowly pour the rest of the glaze over the cake. It should run down the edges in thick streams. You should be able to control the size and length of the streams by the pour.
- Gently press the chopped peanuts into the bottom edge of the cake, creating a 1/2 inch wide band of peanuts where the cake meets the plate.
- Press the shaped peanut brittles into the top of the cake, at evenly spaced intervals.
- Chill the entire cake for approximately 20 minutes, or until glaze is set. Serve at room temperature.
- Cake can be stored, covered with a cake dome or cake saver, at room temperature for up to 3 days.