Chocolate-Caramel Layer Cake

Why this recipe works:

Many chocolate-caramel cakes barely contain enough caramel flavor to merit the name. To ensure caramel flavor in each bite, we sandwich three layers of thick but spreadable caramel filling between layers of deep, dark, moist chocolate cake. For a not-too-sweet caramel that is spreadable but thick enough to stand out between the layers, we cook it until it’s dark (but not burnt) and add extra butter to ensure that it sets up at room temperature and does not ooze. Our thick, satiny chocolate frosting comes together in the food processor in minutes.

Serves 12

Baking spray that contains flour can be used to grease and flour the pans. Both natural and Dutch-processed cocoa will work in this recipe. When taking the temperature of the caramel in steps 3 and 4, remove the pot from the heat and tilt the pan to one side. Use your thermometer to stir the caramel back and forth to equalize hot and cool spots and make sure you are getting an accurate reading.

Ingredients

• Cake

• 1 1/2 cups (7 1/2 ounces) all-purpose flour
• 3/4 cup (2 1/4 ounces) unsweetened cocoa powder
• 1 1/2 cups (10 1/2 ounces) granulated sugar
• 1 1/4 teaspoons baking soda
• 3/4 teaspoon baking powder
• 3/4 teaspoon salt
• 3/4 cup buttermilk
• 1/2 cup water
• 1/4 cup vegetable oil
• 2 large eggs
• 1 teaspoon vanilla extract

• Caramel Filling

• 1 1/4 cups (8 3/4 ounces) granulated sugar
• 1/4 cup light corn syrup
• 1/4 cup water
• 1 cup heavy cream
• 8 tablespoons unsalted butter, cut into 8 pieces
• 1 teaspoon vanilla extract
• 3/4 teaspoon salt

• Frosting

• 16 tablespoons unsalted butter, softened
• 3/4 cup (3 ounces) confectioners' sugar
• 1/2 cup (1 1/2 ounces) unsweetened cocoa powder
• Pinch salt
• 1/2 cup light corn syrup
• 3/4 teaspoon vanilla extract
• 6 ounces bittersweet chocolate, melted and cooled
• 1/4—1/2 teaspoon coarse sea salt (optional)

Instructions

1. 
   
   1. FOR THE CAKE: Adjust oven rack to middle position and heat oven to 325 degrees. Grease two 9-inch round cake pans, line with parchment paper, grease parchment, and flour pans. Sift flour and cocoa into large bowl. Whisk in sugar, baking soda, baking powder, and salt. Whisk buttermilk, water, oil, eggs, and vanilla together in second bowl. Whisk buttermilk mixture into flour mixture until smooth batter forms. Divide batter evenly between prepared pans and smooth tops with rubber spatula.
   2. Bake until toothpick inserted in center comes out clean, 22 to 28 minutes, switching and rotating pans halfway through baking. Let cakes cool in pans on wire rack for 15 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, at least 2 hours.
   3. FOR THE CARAMEL FILLING: Lightly grease 8-inch square baking pan. Combine sugar, corn syrup, and water in medium saucepan. Bring to boil over medium-high heat and cook, without stirring, until mixture is amber colored, 8 to 10 minutes. Reduce heat to low and continue to cook, swirling saucepan occasionally, until dark amber, 2 to 5 minutes longer. (Caramel will register between 375 and 380 degrees.)
   4. Off heat, carefully stir in cream, butter, vanilla, and salt (mixture will bubble and steam). Return saucepan to medium heat and cook, stirring frequently, until smooth and caramel reaches 240 to 245 degrees, 3 to 5 minutes. Carefully transfer caramel to prepared pan and let cool until just warm to touch (100 to 105 degrees), 20 to 30 minutes.
   5. FOR THE FROSTING: Process butter, sugar, cocoa, and salt in food processor until smooth, about 30 seconds, scraping down sides of bowl as needed. Add corn syrup and vanilla and process until just combined, 5 to 10 seconds. Scrape down sides of bowl, then add chocolate and pulse until smooth and creamy, 10 to 15 seconds. (Frosting can be made 3 hours in advance. For longer storage, cover and refrigerate frosting. Let stand at room temperature for 1 hour before using.)
   6. Using long serrated knife, score 1 horizontal line around sides of each cake layer; then, following scored lines, cut each layer into 2 even layers. 7. Using rubber spatula or large spoon, transfer 1/3 of caramel to center of 1 cake layer and use small offset spatula to spread over surface, leaving 1/2-inch border around edge. Repeat with remaining caramel and 2 of remaining cake layers. (Three of your cake layers should be topped with caramel.)
   8. Line edges of cake platter with 4 strips of parchment to keep platter clean. Place 1 caramel-covered cake layer on platter. Top with second caramel-covered layer. Repeat with third caramel-covered layer and top with final layer. Spread frosting evenly over sides and top of cake. Carefully remove parchment strips. Let cake stand for at least 1 hour. (Cake can be made 2 days in advance and refrigerated. Let stand at room temperature for at least 5 hours before serving.) Sprinkle with coarse sea salt, if using. Cut and serve.
   
   
   

Technique

Don't Be Afraid of Caramel

Caramel is simply sugar (sucrose) that’s been heated until it melts, browns, and develops complex flavor. You can use it to make a fluid caramel sauce or chewy or hard candy by adding cream, butter, and other flavorings. The longer the mixture cooks, the more water will evaporate and the stiffer the caramel will become.
Though caramel gets a bad rap for being finicky to make, with the right recipe, it’s easy to overcome its two main pitfalls: The sugar can melt unevenly and burn, or it can seize up and crystallize. The latter happens when some of the sucrose molecules are not hot enough to melt and break down into glucose and fructose and instead bond, creating a grainy texture. Here’s what we do to make a caramel that works.

Technique

Essential Techniques

ADD WATER: Water, which makes a “wet caramel,” helps the sugar dissolve and spread across the pan so that it melts evenly and reduces the risk that some sugar burns before the rest caramelizes.
ADD CORN SYRUP, NOT ACID: Adding acid or corn syrup to sugar as it caramelizes can prevent crystallization; both ingredients interfere with sucrose’s ability to bond with itself.
ACIDS: A small amount of lemon juice, vinegar, or cream of tartar speeds the breakdown of sucrose into fructose and glucose. These molecules dilute the remaining sucrose molecules, decreasing their chances of bonding together before they, too, can break down.
CORN SYRUP: Corn syrup already contains glucose molecules (and water); thus, it dilutes the sucrose molecules faster. For this reason, we prefer it over acids.
USE A HEAVY-BOTTOM SAUCEPAN: Sugar is prone to burning in lightweight cookware, which does not transfer heat evenly. A heavy saucepan helps the sugar cook evenly.
USE TWO LEVELS OF HEAT: Over high heat the sugar can heat unevenly or even burn, but over low heat it can crystallize. That’s because there will be enough heat to evaporate the water, but not enough to melt the sugar, so the sucrose molecules
can bond. We melt the sugar over medium-high heat and then reduce the heat to low to prevent it from burning.

Technique

"Tips" to Avoid

As long as you cook the sugar over a hot enough flame, it will melt, so skip these common caramel techniques.

STIRRING: Stirring the sugar to help it melt isn’t necessary. We simply swirl the pan occasionally as the syrup cooks to even out hot spots.
WASHING/COVERING: Brushing the walls of the pot with a wet pastry brush and covering the saucepan to create condensation are both meant to “rinse” away any sugar molecules that might be clinging to the sides, but they will melt eventually anyway.

Technique

TECHNIQUE: TAKING THE TEMPERATURE OF CARAMEL

Before inserting an instant-read thermometer (which we prefer to a candy thermometer) into the caramel, swirl the caramel to even out any hot spots. Then tilt the pot so that the caramel pools 1 to 2 inches deep and move the thermometer back and forth in the caramel for about 5 seconds before taking a reading. If using a clip-on thermometer, swirl the caramel for at least 15 seconds and tilt the caramel toward the probe.

Technique

Perfecting the Caramel Filling

Our caramel filling is soft enough to spread on the cake layers but not so fluid that it soaks into the cake or drips down the sides of a cut slice.

SOFT, BUT NOT RUNNY

Technique

Do I Really Need to Use Parchment Paper?

It may sound like overkill, but the most effective way to ensure that a cake releases cleanly from a baking pan is to grease the pan, line it with parchment paper, and then grease and flour the parchment and pan sides. The parchment guarantees that the cake pulls away from the pan bottom completely, and a coat of grease and flour on the parchment and up the pan sides helps the batter cling and rise and ensures that the parchment pulls away from the cake bottom without removing large crumbs.

GOT STUCK: Just grease and flour.

CLEAN RELEASE: Grease, flour, and parchment.