Caramel cake is a Southern classic that's famously difficult to make: the frosting hardens quicker than it can be spread, and the cake often collapses under the weight of said frosting.
America's Test Kitchen put their minds together in pursuit of perfecting this recipe. They've subbed in regular flour for cake flour to build a sturdier cake, and the frosting ... well, it has a ton of butter in it. To keep it soft, you see. Don't worry about it, just enjoy it.
1/2 cup buttermilk, room temperature
4 large eggs, room temperature
2 teaspoons vanilla extract
2 1/4 cups all-purpose flour
1 1/2 cups granulated sugar
1 1/2 teaspoons baking powder
1/2 teaspoon baking soda
3/4 teaspoon salt
16 tablespoons (2 sticks) unsalted butter, cut into 16 pieces and softened
12 tablespoons (1 1/2 sticks) unsalted butter, cut into 12 pieces and softened
2 cups packed dark brown sugar
1/2 teaspoon salt
1/2 cup heavy cream
1 teaspoon vanilla extract
2 1/2 cups confectioners' sugar, sifted
For the cake layers: Adjust oven rack to middle position and heat oven to 350 degrees. Grease and flour two 9-inch cake pans. Whisk buttermilk, eggs, and vanilla in large measuring cup. With electric mixer on low speed, mix flour, granulated sugar, baking powder, baking soda, and salt until combined. Beat in butter, 1 piece at a time, until only pea-sized pieces remain. Pour in half of buttermilk mixture and beat over medium-high speed until light and fluffy, about 1 minute. Slowly add remaining buttermilk mixture to bowl and beat until incorporated, about 15 seconds.
Scrape equal amounts of batter into prepared pans and bake until golden and toothpick inserted in center comes out clean, 20 to 25 minutes. Cool cakes in pans 10 minutes, then turn out onto wire racks. Cool completely, at least 1 hour.
For the frosting: Heat 8 tablespoons butter, brown sugar, and salt in large saucepan over medium heat until small bubbles appear around perimeter of pan (see photo at left), 4 to 8 minutes. Whisk in cream and cook until ring of bubbles reappears, about 1 minute. Off heat, whisk in vanilla.
Transfer hot frosting mixture to bowl and, with electric mixer on low speed, gradually mix in confectioners' sugar until incorporated. Increase speed to medium and beat until frosting is pale brown and just warm, about 5 minutes. Add remaining butter, 1 piece at a time, and beat until light and fluffy, about 2 minutes.
To assemble: Place 1 cake round on serving platter. Spread ¾ cup frosting over cake, then top with second cake round. (The cooled frosting stays soft and spreadable longer than other recipes, but it will harden over time. If the frosting does begin to stiffen, you can microwave it for about 10 seconds, or until it returns to a spreadable consistency.) Spread remaining frosting evenly over top and sides of cake. Serve.