Baking Notes:
You should let all your dairy ingredients (including eggs and buttermilk) warm up to room temperature, which makes for a better cake batter.
You can make this cake using all-purpose flour instead of cake flour, however, the cake flour makes a much lighter and more tender cake that is just heavenly.
If you don't have buttermilk, pour 1 1/2 tablespoons white distilled vinegar into a liquid measuring cup, then add whole milk up to the 1 3/4 cups line. Warm in the microwave on high for one minute to curdle the milk. You don't need to let it cool, and can add it to your batter while it's warm.
Note that I live at high altitude (5,000 feet), so my recipes are created for high altitude. Don't let that deter you from trying them if you live at sea level! Please be sure to review this post and this post for all my baking tips and FAQs before baking.
The buttercream recipe makes enough buttercream for the piping design shown here, but if you just want to frost the cake more simply without the piping, you can scale the recipe down to 3/5 of the amounts below: 1 1/2 cups unsalted butter, 3 cups powdered sugar, 1 tablespoon meringue powder, 1/8 teaspoon nutmeg, 1/8 teaspoon coarse Kosher salt, 1/3 cup eggnog, 1 1/2 teaspoons vanilla.
To make this piping design on your cake, first stack and fill the cake layers, then frost all over with a thin crumb coat of the buttercream. Chill the crumb-coated cake in the refrigerator for 30 minutes. Frost the top of the cake with a final layer of buttercream. Use a sharp knife to lightly score the cake with vertical lines around the sides of the cake, to mark where you will start and stop your piped swags. Fit a piping bag with a large open star tip (Wilton #1M), and fill with buttercream. Starting at the bottom, pipe swags around the sides of the cake, starting and stopping at your scored lines. Work your way up the cake until the sides of the cake are covered.
Cardamom Cake with Eggnog Buttercream
Cake.
1 3/4 cups whole buttermilk
1 teaspoon ground cardamom
1 teaspoon espresso powder or instant coffee
1/4 teaspoon ground nutmeg
1 3/4 cups dark brown sugar, lightly packed
3 large eggs
3/4 cup vegetable oil
2 teaspoons vanilla
2 3/4 cups cake flour
1 3/4 teaspoons baking powder
1 1/4 teaspoons baking soda
1 teaspoon coarse Kosher salt
Buttercream.
2 1/2 cups unsalted butter, softened to room temperature
5 cups powdered sugar
1 1/2 tablespoons meringue powder
1/4 teaspoon ground nutmeg
1/4 teaspoon coarse Kosher salt
1/2 cup eggnog
2 1/2 teaspoons vanilla
Cake.
Preheat the oven to 350 and spray the bottoms of three 8-inch round cake pans with non-stick spray.
In a small saucepan, bring the buttermilk just to a simmer. Remove from the heat and stir in the cardamom, espresso powder and nutmeg. Let steep for about 15 minutes.
In a large bowl, whisk together the spiced buttermilk, brown sugar, eggs, oil and vanilla.
In a separate bowl, sift together the cake flour, baking powder, baking soda and salt. Add the dry ingredients to the wet and whisk by hand for about 1 minute, just until smooth and mostly lump-free.
Divide the batter between the pans and bake on the middle oven rack for about 22-25 minutes, until a cake tester comes out clean and the center of the cake springs back when lightly touched. Set the cake pans on a wire rack, cover loosely with a clean kitchen towel, and cool completely before frosting.
Buttercream.
In the bowl of your stand mixer fitted with the whisk attachment, beat the butter for one minute until smooth. With the mixer on low, add the powdered sugar, meringue powder, salt and nutmeg, and mix just to combine. Add the eggnog and vanilla, and beat on medium high for about 4-5 minutes, scraping the bowl occasionally, until very light and fluffy.
Frost the cooled cake using the instructions noted in the baking tips above.
Recipe from Curly Girl Kitchen