OH WAIT. I did.
My friend Claire came to visit for her 30th birthday a couple weeks ago. I love birthdays because it means an opportunity for me to bake a cake. For this illustrious event, I decided to make one of my favorites, dark chocolate layer cake soaked with kahlua, filled and frosted with dark chocolate ganache.
This cake is decadent. A thin slice is plenty and it goes perfectly with a scoop of vanilla ice cream. What really makes this cake for me is a technique I learned in a cake decorating class I took. The trick is using fishing line, sewing thread, or dental floss to cut the cake layers in half, so you get twice as many. This means twice as much filling, which is awesome. To do this, you score the cake evenly around the side, put the string in the groove, and then cross it and pull it through until it slices the layer into two even layers.
The next step is to soak the first layer in Kahlua using a pastry brush. This does a couple of things. It acts as a crumb coat, which basically means it brushes off the crumbs (or adheres them to the cake), allowing the filling to go on more smoothly. It also gives the cake some extra moisture and enhances the dark chocolate/coffee flavor it already has.
Next spread the ganache over the first layer that you have soaked with the Kahlua.
Put the second layer on and repeat. Once you have the fourth layer on, soak it in the Kahlua. Now you’re ready to frost.
I do my frosting on a turntable. They aren’t super expensive, and if you do much frosting, they are definitely the way to go. You can stick your cake stand/plate/whatever right on top of it and stay in one place as you turn the stand. Once you’ve frosted, you end up with a lovely cake, and the four layers inside look super impressive (ignore the frosting I got on the tablecloth!)
For cake layers
3 ounces fine-quality semisweet chocolate (I use the pound plus chocolate from Trader Joes)
1 1/2 cups hot coffee
3 cups sugar
2 1/2 cups all-purpose flour
1 1/2 cups unsweetened cocoa powder (not Dutch process)
2 teaspoons baking soda
3/4 teaspoon baking powder
1 1/4 teaspoons salt
3 large eggs
3/4 cup vegetable oil
1 1/2 cups well-shaken buttermilk
3/4 teaspoon vanillaFor ganache frosting
1 pound fine-quality semisweet chocolate
1 cup heavy cream
2 tablespoons sugar
2 tablespoons light corn syrup (I have made it with and without the corn syrup and I don’t really think it makes a difference, but if it’s important to you, go for it)
1/2 stick (1/4 cup) unsalted butter
OPTIONAL: 3-4 tablespoons Kahlua
For crumb coat
4 – 6 oz. Kahlua
two 10- by 2-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.
[NOTE: I hate chopping chocolate. I think it’s a pain in the patootie. Usually I skip that and just put the coffee and chocolate together in a bowl over some boiling water until it’s all melted. It’s worked fine for me.]
Into 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 colored (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, 1 hour to 1 hour and 10 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.
Finely chop chocolate. In a 1 1/2- to 2-quart saucepan bring cream, sugar, and corn syrup (if using) to a boil over moderately low heat, whisking until sugar is dissolved. Remove pan from heat and add chocolate, whisking until chocolate is melted.
[Note: Really the same note as before, I did this using a double-boiler method and it worked fine. If you want to be a purist, that’s okay too, but I am lazy. If you do that, still remove it from the heat before you add the butter.]
Cut butter into pieces and add to frosting, whisking until smooth. Add Kahlua, if using.
Transfer frosting to a bowl and cool, stirring occasionally, until spreadable (depending on chocolate used, it may be necessary to chill frosting to spreadable consistency).
Cut cake layers in two using string method. Soak each layer in Kahlua using a pastry brush and cover with chocolate ganache before topping with next layer. Frost once all layers are on the cake.
Cake keeps, covered and chilled, 3 days. Bring cake to room temperature before serving.