Chocolate Raspberry Layer Cake

It's been firmly established that chocolate is my kryptonite, but do you know what makes chocolate even better? Raspberries. I love the flavour of dark chocolate mixed with the tartness of raspberries, so much that I've made a rugelach with this combination.

I first discovered this complementary flavour when I was gifted a chocolate mousse cake filled with a mixed berry coulis, finished with a dark chocolate glaze. It instantly became my favourite cake and in "treat yo' self" mode, purchased it for myself on my birthdays.

I then discovered this recipe and it was like the universe knew exactly what I wanted in a cake. Moist, flavourful chocolate cake? Raspberry filling? Chocolate ganache frosting? Check, check and check. I've made this cake several times and it has never disappointed me.

Some words of advice: this cake is delicate so handle with care. The original recipe called for two 10-inch cake pans baked for about one hour, but I prefer using three 9-inch cake pans because you don't have to divide the layers into two. Freeze the cake so that it hardens to make cutting/levelling the layers easier. I actually baked the layers in advance, stored them in the freezer well wrapped in plastic, and assembled the cake several days later (hence the condensation on my frosting, as the ganache froze against my cake). Deb has some great tips on making layer cakes.

Yes, this cake requires some effort but is so, so worth it, especially if you're a chocolate lover.

Chocolate Raspberry Layer Cake
Adapted from Smitten Kitchen via Picky Cook

I decreased the sugar in the cake batter from three cups to two, as I prefer my desserts less sweet.

Cake layers
3 ounces (85 grams) semi-sweet chocolate
1 1/2 cups (355 ml) hot brewed coffee
2 cups (400 grams) sugar
2 1/2 cups (315 grams) all-purpose flour
1 1/2 cups (approximately 130 grams; weights vary between brands) unsweetened cocoa powder (not Dutch-process)
2 teaspoons (10 grams) baking soda
3/4 teaspoon (4 grams) baking powder
1 1/4 teaspoons (7 grams) table salt
3 large eggs
3/4 cup (175 ml) vegetable oil
1 1/2 cups (355 ml) well-shaken buttermilk
3/4 teaspoon vanilla

Raspberry filling
2 10-ounce bag frozen raspberries, thawed
1/2 cup sugar
2 tablespoons cornstarch

Ganache frosting
1/2 pound (228 grams) fine-quality semisweet chocolate, such as Callebaut
1/2 cup (118 ml) heavy cream
1 tablespoon (13 grams) sugar
1/4 stick (1/8 cup or 27.5 grams) unsalted butter

Special equipment: three 9-inch round cake pans

Make cake layers:

Preheat oven to 300°F and grease pans. Line bottoms with rounds of parchment paper and grease paper.

Finely chop chocolate and in a bowl, combine with hot coffee. Let mixture stand, stirring occasionally, until chocolate is melted and mixture is smooth.

In a large bowl, sift together sugar, flour, cocoa powder, baking soda, baking powder, and salt. In another large bowl with an electric mixer, beat eggs until thickened slightly and lemon coloured (about 3 minutes with a standing mixer or 5 minutes with a hand-held mixer). Slowly add oil, buttermilk, vanilla, and melted chocolate mixture to eggs, beating until combined well. Add sugar mixture and beat on medium speed until just combined well.

Divide batter between pans and bake in middle of oven until a tester inserted in center comes out clean, about 40 minutes.

Cool layers completely in pans on racks. Run a thin knife around edges of pans and invert layers onto racks. Carefully remove parchment paper and cool layers completely. Cake layers may be made 1 day ahead and kept, wrapped well in plastic wrap, at room temperature.

Make raspberry filling:

Puree the raspberries in a food processor, blender or immersion blender. Press the puree through a fine-mesh strainer with the back of a spoon, removing the seeds. Heat the puree in a small pot with the sugar and cornstarch until mixture boils, stirring constantly. As it boils, it should quickly thicken.

Let it cool complete before spreading it over the layers.

Make ganache frosting:

Finely chop chocolate. In a small saucepan, bring cream and sugar to a boil over moderately low heat, whisking until sugar is dissolved. Remove pan from heat and add chocolate, whisking until chocolate is melted. Cut butter into pieces and add to frosting, whisking until smooth.

Transfer frosting to a bowl and cool, stirring occasionally, until spreadable.

Assemble cake:

With a long serrated knife, level out the top of the cake layers (if necessary). Lay the bottom layer on a plate and slip pieces of parchment paper underneath the edge of the cake all around the circumference (this keeps the plate clean). Take half of the raspberry filling and spread it over the layer. Stay about half an inch away from the edge. Lay the next layer on top. Spread another half of the raspberry filling. Put the final layer on the top of the cake. Gently make sure all the layers are lined up.

Pour some of the ganache on the top layer and with an offset spatula, start smoothing out the frosting, gently pushing it toward the edge. Add more until you have worked the ganache down over the sides of the cake.

Remove parchment paper. Decorate the cake with fresh raspberries. Cake keeps, covered and chilled, three days. Bring cake to room temperature before serving.