Vanilla Cake with Tiramisu Buttercream & Bittersweet Ganache Filling
- 3 3/4 C Cake Flour.
- 2 1/2 C Sugar.
- 1 Tbsp + 2 3/4 Tsp Baking Powder.
- 1/2 Tsp Salt.
- 10 oz Unsalted Butter, room temperature.
- 1 1/4 C + 1/3 C Buttermilk.
- 5 Whole Eggs.
- 2 Egg Yolks.
- 2 1/2 Tsp Pure Vanilla Extract.
For Buttercream (half this amount if using fondant):
- 6 Large Egg Whites.
- 1 1/2 C Sugar.
- 1 Tsp Pure Vanilla Extract.
- 20 oz Unsalted Butter, room temperature.
- 2 Tbsp Warm Water.
- 1 Tbsp Instant Coffee.
- 1/3 C Heavy Cream.
- 3 oz Bittersweet Chocolate, chopped.
To make the cake:
- Pre-heat your oven to 325 degrees F. Butter three 9-inch round cake pans. Line the bottom of each pan with a round of parchment or waxed paper and butter the paper.
- Combine the cake flour, sugar, baking powder, and salt in a large mixer bowl. With the mixer on low speed, blend for about 30 seconds. Add the butter and 1 1/4 C of the buttermilk. Mix on low speed briefly to blend; raise the speed to medium and beat until light and fluffy, about 2-3 minutes.
- In a smaller bowl, whisk together the whole eggs, egg yolks, vanilla, and the remaining 1/3 C of buttermilk until well blended. Pour one-third of the egg mixture into the cake batter at a time, folding it in completely after each addition. There will be 9 cups of batter; pour 3 cups into each pan.
- Bake 26-28 minutes, or until a toothpick inserted into the centre comes out clean.
- * My oven required an extra 15 minutes of cooking time since the top was still a little liquidy after 28 minutes - adjust accordingly.
- Remove from the oven and let cool a few minutes.
- Turn the layers out onto wire racks by placing a rack on top of a pan, inverting it, and lifting off the pan. Peel the paper liners off and let cool completely. When the layers have cooled, place a cardboard cake board on top of a layer, invert again, and lift off the rack. To make layers easier to handle, wrap them on their boards completely in plastic wrap, so they don't dry out, and refrigerate them.
To make Buttercream:
- Combine the sugar and egg whites in a large heatproof bowl over a saucepan of simmering water (double boiler) and whisk constantly until it feels hot to the touch - about 5 minutes. The sugar should be dissolved and the mixture will look like marshmallow cream.
- Remove from the heat and transfer to a cool bowl and blend on high speed until mixture is completely cooled and stiff peaks form - about 6 minutes. Beat in vanilla and add butter 2 Tbsp at a time, mixing well on low speed after each addition. Beat until smooth - about 3 minutes.
- Stir instant coffee into warm water until dissolved. Add, 1 Tsp at a time, to buttercream, mixing well after each addition. Continue until you are satisfied with the strength of the coffee flavour (Love & Olive Oil used about 1 Tbsp, I used about 3).
- Set aside until ready to use.
To make Ganache:
- Place chopped chocolate in a heat proof bowl.
- In a heavy saucepan set over medium heat, bring the heavy cream to a boil. Remove from the stove and pour over chopped chocolate. Let stand 2 minutes and then stir until fully combined. Let cool until just firm enough to spread onto cake layers.
- After levelling the cake layers as necessary (chop off excess round top bits), place one cake layer on a plate, flattest side up. Brush with sugar syrup if desired (it will help keep cake moist - I omitted this step). Spread half the ganache evenly over the top, followed by approx 3/4 cup of the buttercream. Repeat with the second cake layer. Top with the third cake layer and lightly crumb coat the cake with more buttercream. At this point you can either cover the cake with fondant, or frost it with a thick layer of buttercream.