Buttermilk Birthday Cake with Malted Chocolate Frosting
Tender, moist layers of vanilla bean buttermilk cake filled and frosted with a gloriously smooth malted chocolate frosting and topped with a flurry of white nonpareils.
For the Best-Ever Buttermilk Cake layers:
- 3 cups 345 g cake flour
- 2 cups 410 g superfine sugar
- 1 tablespoon plus 1 teaspoon baking powder
- 3/4 teaspoon salt
- 3/4 cup plus 2 tablespoons (200 g cold unsalted butter, cut into pieces)
- 2 tablespoons 30 ml vegetable oil
- 1 1/4 cups 300 ml buttermilk, room temperature
- 2 teaspoons vanilla bean paste or pure vanilla extract
- 5 large eggs (room temperature)
For the Malted Chocolate Frosting:
- 2 1/4 cups 510 g unsalted butter, room temperature
- 4 cups 500 g confectioners' sugar
- 1/2 cup Ovaltine or malted milk powder
- 1/3 cup 80 ml whipping cream
- 2 teaspoons pure vanilla extract
- Pinch of salt
- 1/4 cup 60 ml sour cream or plain Greek yogurt
- 9 ounces 265 g premium dark chocolate, chopped or callets
- White nonpareils for decorating (optional - or use Rainbow for even more fun!)
You will also need:
- Large pastry bag
- Decorating tip Ateco #887
For the Best-Ever Buttermilk Cake layers:
- Preheat the oven to 350° F. Spray the bottoms of three 8-inch round cake pans and line with parchment rounds. Set aside.
- In a large measuring cup with a spout, lightly whisk the eggs, 1/4 cup of the buttermilk and the vanilla bean paste. Set aside.
- In the bowl of an electric mixer fitted with the paddle attachment, whisk together the flour, sugar, baking powder and salt. With the mixer set to low speed, add the cold butter one piece at a time, about 10 seconds apart. Add the vegetable oil and continue mixing on low speed until all of the butter and oil have been blended and there are no clumps. Mixture should have a fine crumbly, cornmeal-like texture.
- Add the remaining buttermilk to these dry ingredients, and mix on medium speed for 4 minutes. Scrape the sides and bottom of the bowl to ensure all of the ingredients are well incorporated. Reduce the speed to low and gradually add the egg mixture; once the mixture has been added, increase speed to medium and beat for 1 minute. Gently fold batter once or twice (but no more) to ensure the egg mixture has all been incorporated.
- Divide batter evenly among the 3 prepared pans (use a kitchen scale to ensure 3 even layers--each layer should weight about 475g). Place two of the cake pans on the middle rack and bake until a toothpick inserted into the center comes out with a few crumbs but no batter, about 23 minutes. Repeat with the final layer. Let the layers cool in the pans for 10 minutes, then loosen sides with thin metal spatula or knife, and carefully turn out onto wire racks, peel of the paper liners, and let cool completely.
For the Malted Chocolate Cloud Frosting:
- Put all of the ingredients, except the melted chocolate, in a food processor, and pulse until smooth, about 1 minute. Add the melted chocolate and pulse again until glossy and smooth. If the frosting is too soft, you can refrigerate the frosting until it thickens slightly, about 15 minutes, but it should be ideal spreading consistency after pulsing.
Assembly of the Buttermilk Birthday Cake:
- Put a dollop of frosting on an 8-inch thin cake board (or cake plate) or 10-inch scalloped cake board.
- Put your first layer top-up on the cake board or plate, and spread about 1 cup of frosting evenly across layer. Put the second cake layer on top and repeat with another layer of frosting. Put the final cake layer top-down. Cover the cake with a thin layer of frosting to seal in the crumbs (crumb coat) and then refrigerate the cake until the frosting has firmed up slightly, about 30 minutes Repeat with a thicker layer of frosting, this time working to achieve a smooth finish.
To pipe the large swirl border:
- Fit a large pastry bag with a large closed star tip, such as Ateco #887, and fill about 2/3 full with frosting. Hold the pastry bag tip directly above the cake (I like to stand on a stool when I do this, so I can better see the top of the cake). Begin anywhere on the perimeter and gently apply enough even pressure to the pastry bag to keep the frosting flowing easily but slowly--as soon as the frosting begins to touch the cake, pipe one full tight circle, creating a rosette-style pattern, and drag the frosting to the right in one fluid motion and release pressure. Lift tip away from cake. Beginning just overtop of where you left off, repeat. Do this around the entire perimeter of the cake. Repeat this technique over your existing border for an extra swirly finish.
- Top the border and sides of cake with a some white nonpareils (for the sides, I "toss" small pinches of the nonpareils at the bottom of the cake and they bounce up). You can also use Rainbow Nonpareils, Chocolate Crunchy, or any other medley your heart desires! The cake will keep refrigerated for up to 3 days--best served at room temperature.
- For the cake flour, I used Bob's Red Mill Super-Fine Cake Flour, but you can use any cake flour.
- For the vanilla bean paste, I used Nielsen-Massey Vanilla Bean Paste.
- For the frosting, I used dark chocolate Callebaut callets (chips) 54.5% cocoa solids. Just a reminder that I increased the frosting recipe by about 25% because the big swirls require a lot of it--if you aren't going to do the swirls, you can decrease the frosting recipe by this amount.
- I added Ovaltine to the frosting for a nostalgic malt flavour (just be sure to use original and not chocolate flavoured).
- To decorate the top swirl I used Ateco #887. You can use Wilton 1M, which is more commonly owned it seems, but your swirls just won't be as, well, swirly, and a smidge smaller. It will still be gorgeous!