Yesterday was my turn to bring snacks to my community group, and I decided to make a raspberry chocolate truffle cake. I saw this cake on Annie's Eats, but I tweaked it slightly. I have a chocolate cake recipe that I love and will never stray from. I used the raspberry filling and frosting recipe and the chocolate ganache recipe that hers called for. I decided not to add the chocolate glaze just because I thought it had enough chocolate and richness as it was. Below is my finished product. If you would like the original recipe, you can find it here.
He does a much better job than me.
Raspberry filling:16 oz. frozen raspberries, thawed
1/3 cup sugar
3 tbsp. cornstarch
1 tsp. lemon juice
8 oz. bittersweet chocolate, finely chopped
1 cup heavy cream
3 tbsp. unsalted butter, at room temperature
1 cup sugar
4 large egg whites
21 tbsp. unsalted butter, at room temperature
1/3 cup strained raspberry puree
½ tsp. vanilla extract
To make the raspberry filling, drain the thawed berries, reserving the juice in a liquid measuring cup. Add enough water so that the total liquid equals 1¼ cups. Add the liquid to a medium saucepan with the sugar and cornstarch. Heat over medium-high heat, whisking occasionally, until the mixture begins to bubble and thicken. Continue whisking so no lumps form. Once thickened, remove from the heat and whisk in the lemon juice. Fold in the drained berries with a spatula. Cover and chill until ready to use. (The filling will continue to thicken as it chills.)
To make the ganache, place the chopped chocolate in a heatproof bowl. Heat the cream in a saucepan and bring to a simmer. Immediately remove from the heat and pour the hot cream over the chopped chocolate. Let stand 1-2 minutes, then whisk together until a smooth, thick ganache is formed. Whisk in the butter 1 tablespoon at a time until completely incorporated. Let the ganache sit to thicken a bit so that it is suitable for spreading and piping. (To speed thickening, place the bowl in the fridge or freezer and whisk every 10 minutes to ensure even cooling until the desired consistency is reached.) Transfer about ½ cup of the thickened ganache to a pastry bag fitted with a plain round tip about ½-inch in diameter. Reserve another ½ cup of ganache in a small bowl or container. (This can be used later for decorative detailing, if desired.)
To assemble the cake, place one of the cooled cake layers on a cake board or serving platter. Spread ½ cup of the ganache in an even layer over the cake. Using the reserved ganache in the pastry bag, pipe a border around the perimeter of the cake layer. This will act as a well to help hold in the raspberry filling. Spoon some of the raspberry filling inside the ganache border in an even layer. Top with another layer of cake and repeat this process, layering with another ½ cup of ganache and additional raspberry filling. Top with the remaining cake layer.
To make the raspberry frosting, combine the sugar and egg whites in a heatproof bowl set over a pot of simmering water. (I used my mixer bowl here to dirty one less dish.) Heat, whisking frequently, until the mixture reaches 160° F and the sugar has dissolved. Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment. Beat on medium-high speed until stiff peaks form and the mixture has cooled to room temperature, about 8 minutes. (The bowl should be cool to the touch.) Reduce the speed to medium and add the butter, 2 tablespoons at a time, adding more once each addition has been incorporated. If the frosting looks soupy or curdled, continue to beat on medium-high speed until thick and smooth again, about 3-5 minutes more (or longer – don’t worry, it will come together!) Blend in the raspberry puree and vanilla until smooth and completely incorporated, scraping down the sides of the bowl as needed.
Frost the top and sides of the assembled cake with the raspberry buttercream, smoothing the surface as much as possible. Chill until ready to serve.