1. Requires standing mixer and an ice bath, prepared ahead of time and kept in freezer or fridge until ready.
2. Mind your chocolate!! For the frosting, only use semisweet chocolate bars (not chips; they don't melt like chocolate bars or baker's chocolate).
3. For best results, don't make the frosting until the cakes are cooled, and use the frosting as soon as it is ready.
4. If the frosting gets too cold and stiff to spread easily, wrap the mixer bowl with a towel soaked in hot water and mix on low speed until the frosting appears creamy and smooth.
5. Refrigerated leftover cake should sit at room temperature before serving until the frosting softens.
6. If one specific type of chocolate isn't available (i.e. you only have semi-sweet chips or dark chocolate bars), look for appropriate substitutions on this webpage at AllChocolate.com.
- "If you are using bars with more than 60% or 70% cacao in a recipe not specifically designed for them, follow this general rule: use 25% to 35% less chocolate than called for in the recipe and add up to 1-1/2 teaspoons more granulated sugar for each ounce of chocolate in the original recipe."
16 ounces semisweet chocolate, finely chopped
8 Tbl unsalted butter (1 stick)
1/3 cup sugar
2 Tbl corn syrup
2 tsp vanilla
1/4 tsp table salt
1-1/4 cups heavy cream (cold)
1. Prepare a saucepan with 1" of barely simmering water. Place chocolate in heatproof bowl set over saucepan, stirring occasionally. When melted chocolate is smooth, remove from heat and set aside.
2. Meanwhile, in small saucepan, heat butter over medium-low heat until melted.
3. Increase heat to medium; add sugar, corn syrup, vanilla, and salt. Stir with heatproof rubber spatula until sugar is dissolved, 4 to 5 minutes.
4. Add melted chocolate, butter mixture, and cream to clean bowl of standing mixer and stir to thoroughly combine.
5. Place mixer bowl over ice bath and stir mixture constantly with rubber spatula until frosting is thick and just beginning to harden against sides of bowl, 1 to 2 minutes (frosting should be 70 degrees; if it's 75, it won't really whip; if it's 65 it will be too hard and get gritty).
6. Place bowl on standing mixer fitted with paddle attachment and beat on medium-high speed until frosting is light and fluffy, 1 to 2 minutes. Stir with rubber spatula until completely smooth.
7. TO FROST CAKE: Place one cake layer, right-side up, on serving platter or cardboard round. Spread 1-1/2 cups frosting evenly across top of cake with spatula.
8. Place second cake layer on top, upside down, then spread remaining frosting evenly over top and sides of cake. Cut into slices and serve.