Heart-Shaped Chocolate Caramel Layer Cake

Three years after I first attempted a recipe using our heart-shaped cake ring, I decided it was time to bust it out again for The Gastronomer's anniversary present this year.  I wasn't sure what kind of cake to make, but I figured that pretty much any 8-9 inch layer cake recipe could probably be adapted for the heart-shaped pan.  Fortunately, a few days before showtime, the perfect recipe fell into my lap at the L.A. Times Book Fair.  The Gastronomer and I were unsurprisingly hanging out around the food stage, and we settled in to watch a cooking demo and Q&A by Alex Guarnaschelli.  I was vaguely familiar with her but hadn't really formed much of an opinion during my rare viewings of Iron Chef and Chopped.  Anyway, it turned out that she was HILARIOUS, and impressively able to come up with funny and relevant stories in response to all manner of unscripted audience questions, all while making meatballs and baking an extravagant cake.

The featured cake was this yellow layer cake with chocolate buttercream frosting and caramel topping, which apparently was her favorite childhood birthday cake. Given The Gastronomer's penchant for caramel, I immediately knew that this was the perfect recipe to make into a heart cake.  Fortunately, it was available online from ABC News.

The cake took a long time, partly because I only had one heart-shaped cake ring and thus had to make and bake the batter in two batches, and partly because I was overly cautious at every step (particularly in caramelizing the sugar--this was my first time, and I literally spent 30 minutes with the heat too low and nothing much happening before The Gastronomer came into the kitchen and helped me turn the uneven mixture of candy chunks I had created into an amber caramel sauce).  Nevertheless, it was worth it--the end result was impressive and delicious.  The crunchy candy-like caramel topping was an awesome addition to a traditional layer cake.  Strangely, even though it was basically pure sugar, I thought it balanced out the sweetness of the frosting somehow--usually cakes with this much icing are too much for me.

Recipe courtesy of Alex Guarnaschelli via abcnews.go.com.

For Cake

• 2 cups all-purpose flour 
• 2¼ teaspoons baking powder
• ¾ teaspoon kosher salt
• 16 tablespoons (2 sticks) lightly salted butter, at room temperature, plus more for greasing the pans
• 2 cups sugar
• 6 large eggs
• Grated zest and juice of 1 lemon

For Frosting

• 14 ounces bittersweet chocolate, roughly chopped (about 2¾ cups)
• 1¼ cups sugar
• ½ teaspoon kosher salt
• 2 cups heavy cream
• 1 teaspoon vanilla extract
• 12 tablespoons (1½ sticks) lightly salted butter, cut into thin slices

For Caramel Topping

• 1 cup sugar
• 2 teaspoons light corn syrup
• Flaky sea salt, such as Maldon (for garnish) 

Make Cake

Preheat the oven to 350°F. Grease two 8-inch round cake pans (or heart-shaped pans!) with butter.  In a bowl, stir together the flour, baking powder, and salt. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth, 2 to 3 minutes. Add the sugar and continue beating until the mixture becomes fluffy, 5 to 8 minutes. Add the eggs, one by one, taking care that each one is thoroughly integrated before adding the next. Add the lemon zest and lemon juice and then the flour mixture and mix until fully blended. Do not overmix.

Divide the batter between the prepared cake pans. Bake until the centers are firm and the tip of a small knife emerges clean when it pierces the center of each cake, 30 to 40 minutes. Remove from the oven, unmold the cakes, and allow to cool thoroughly on a rack.

Make Frosting and Frost Cake
 
In a medium bowl, combine the chocolate, sugar, and salt. In a medium saucepan, bring the cream and vanilla to a simmer, about 5 minutes. Pour over the chocolate and stir until all of the chocolate has melted. Gently whisk in the butter slices. Set aside to cool.

When the frosting is cool, whip the frosting in the bowl of a stand mixer fitted with a whisk attachment to lighten it, 1 to 2 minutes. Split each cake in half horizontally so you have 4 equal layers. Put the first cake layer on a rack set over a baking sheet, cut side up. Frost the layer and the remaining ones, stacking them neatly and uniformly on top of each other. Frost the entire outside of the cake as well. Refrigerate for at least 30 minutes so it gets cold.

Make Caramel
 
In a large skillet, heat the sugar and corn syrup over medium-low heat until the sugar melts and turns a caramel color. Swirl the sugar gently in the pan as it cooks so it browns evenly. Take the skillet and pour the caramel over the top of the cake, allowing it to drip down the sides and onto the pan below. It is normal that the hot caramel will melt the frosting slightly. Try to pour it in as even and as thin a layer as you can over the cake.  If the caramel cools before pouring, warm it gently over low heat to loosen it again. Allow the caramel topping to cool and harden on top of the cake, at least 5 to 10 minutes before serving, or up to 1 hour. Sprinkle with a pinch of Maldon salt. When ready to slice, use the heel of a knife to crack the caramel top before cutting slices.  Alex Guarnaschelli recommends that the cake shouldn't be refrigerated and should be served at room temperature, but we found that it was also delightful re-heated in the microwave after being stored in the fridge.

Yield: 6 to 8 servings
Estimated Start-to-Finish Time: Not given
Actual Start-to-Finish Time: 3-4 hours