Life is Great

Salted Caramel Chocolate Fudge Cake

Cake recipe similar to here, salted caramel Swiss meringue buttercream and chocolate fudge frosting recipes from Rosie Alyea's original cake post.
Yield: A 3-layer 8-inch round cake, 4 cups salted caramel Swiss meringue buttercream

Notes:

Salted caramel Swiss meringue buttercream: Various online bloggers had trouble making Martha Stewart's salted caramel buttercream. Personally I chose not to follow her method on making the buttercream with beaten butter - in my weather condition, it would've been a disaster. So I stuck to my standard 5 egg whites SMBC recipe and simply add in the caramel sauce in the end. Have all your buttercream mise en place ready to start as soon as you finish cooking the caramel. If the caramel sauce is too thick by the time your SMBC is ready, simply warm it up on the stove a touch and let it cool down till just thin enough to pour into the spinning mixer to mix. If the buttercream end up being slightly soft due to the heat of the caramel, chill in the fridge for 10-15 minutes then whip it up again before using.

Dark chocolate fudge frosting: Essentially to me this is like making hot fudge but whipped with sugar. In a tropical weather like mine, you will most likely end up with a frosting too runny to use. I cooled it down as per cooling down a ganache frosting - 15-20 minutes in the fridge, fold with a rubber spatula, repeat with reducing fridge time, till frosting is the correct consistency to ice.

Dark chocolate cake layers:

• 2 3/4 cups/11 ounces/312 grams all-purpose flour
  
• 2 2/3 cups sugar/1 pound 5 ounces/605 grams (I reduced it to 450 grams)
  
• 2 3/4 teaspoon baking soda
  
• 2 3/4 teaspoon baking powder
  
• 1 cup/4 ounces/113 grams unsweetened Dutch-process cocoa powder (I used Valrhona)
  
• 1 3/4 teaspoons salt
  
• 150 millilitres vegetable oil (I used grape seed)
  
• 280 millilitres buttermilk (I made mine with fresh whole milk plus 1 tablespoon white wine vinegar)
  
• 4 eggs
  
• 260 millilitres hot coffee (I used pressed espresso)
  
• 2 tablespoons of vanilla

Salted caramel Swiss meringue buttercream:

• 350 grams castor sugar - separated into 220 grams and 130 grams portions
  
• 1/4 cup/60 millilitres water
  
• 1/4 cup/60 millilitres heavy cream, room temperature
  
• generous pinch of sea salt (for the caramel, and additional sea salt, preferably Fleur de Sel, for sprinkling)
  
• 5 large egg whites
  
• pinch of salt (for meringue)
  
• 2 tablespoons pure vanilla extract
  
• 300 grams unsalted butter

Dark chocolate fudge frosting:

• 1/4 cup + 2 tablespoons/45 grams/1.5 ounces unsweetened Dutch-process cocoa powder (I used Valrhona)
  
• 1/4 cup + 2 tablespoons/90 millilitres /3 ounces boiling water
  
• 1 1/2 cups/3 sticks/341 grams/12 ounces unsalted butter, room temperature
  
• 1/2 cup/63 grams/2 ounces confectioners’/icing/powdered sugar, sifted
  
• pinch of salt
  
• 1 pound/454 grams/16 ounces good-quality semi-sweet chocolate, melted and cooled (I used Valrhona Araguani 72% fèves)

Prepare the cake layers: Preheat oven to 350°F/180°C/gas mark 4. Grease and line 3 8-inch cake tins, dust with cocoa powder, tapping out the excess. In large bowl, sift in all the dry ingredients. Add all remaining ingredients to the bowl with the dry ingredients and mix well with a heavy hand whisk for about 2 minutes. Pour into prepared tins (batter will be quite liquid). Tap the tins on the counter a few times. Bake each layer for about 20-25 minutes, rotating once (if necessary). Cake is done when toothpick or skewer comes out barely clean. Refrain from overbaking. Cool completely on a wire rack in the pan.

Prepare the salted caramel Swiss meringue buttercream: Prepare the salted caramel first. Place 130 grams/5 ounces/1/2 cup + 2 tablespoons of the castor sugar and the water in a medium saucepan to a boil over medium heat. Brush down the sides of the pot with a dampened pastry brush to prevent sugar crystals from forming (in a hot and humid weather like Singapore, you can skip this step). Stop stirring and cook until caramel is dark amber, gently swirling from time to time. Remove from heat, and gradually add the cream, whisking by hand until smooth. It will be splatter slightly (less if cream is room temperature). Whisk in sea salt and vanilla. Let cool and start the buttercream immediately.

Combine the egg whites, sugar and salt in a heatproof bowl over a pan of simmering water. Whisk frequently, keeping it over the heat, until the mixture reaches about 160°F/70°C (I have always just done this by touch) and the sugar has dissolved (rub some between your fingers - if it feels grainy, it hasn't dissolved). Transfer the mixture to a mixer with a whisk attached and beat on medium-high for 8 minutes, until stiff peaks have formed and the mixture has cooled to room temperature. Turn down the speed to medium and start adding small chunks of butter, checking that it has incorporated before adding more. Keep beating until it comes together, this will take about 5 minutes. With the mixer running on low, drizzle in the salted caramel sauce gradually, beating until well combined between each addition. Refrain from eating the buttercream (lick the leftover caramel sauce instead).

Prepare the dark chocolate fudge frosting: Combine cocoa powder and the boiling water in a small bowl or glass measuring cup, and stir until it cocoa has dissolved. In an electric mixer fitted with the paddle attachment (flat beater), beat the butter, the icing sugar, and salt on medium-high speed until it is pale and fluffy–about 5 minutes. Reduce mixer speed to low, and add melted chocolate (cooled), beating until combined and scraping down the sides of the bowl as needed. Beat in the cocoa mixture until well incorporated.

Assemble the cake: Dollop a small bit of buttercream onto your intended serving plate/cake board. Place one cake layer on and layer on about 3/4 cup of the salted caramel buttercream. Repeat with the second layer of cake. Place the last layer of cake on top and coat the entire cake with a crumb coat using the chocolate fudge frosting. Refrigerate cake for 15-20 minutes. Once the crumb coat is set, remove cake and cover with the remaining fudge frosting. Return cake to the fridge and let it set, about 15-20 minutes. Sprinkle with fleur de sel or flaked sea salt to decorate.

Do ahead: Cake layers can be made up to 3 days ahead. Cling wrap each layer 3 times and freeze till required. Salted caramel Swiss meringue buttercream can be made ahead. Keep in airtight container in refrigerator for up to one week, leaving out at room temperature when needed, rewhipping in mixer for 5 minutes. Freeze for up to 6-8 weeks. To thaw, place on counter overnight, and rewhip for 5 minutes with paddle attachment in an electric mixer. Dark chocolate fudge frosting can be refrigerated for up to 5 days, or frozen for up to 1 month in an airtight container. Before using, bring to room temperature (usually overnight on counter does the trick), and beat on low speed until smooth.