For the Cake:
- 1 cup unsalted butter at room temperature
- 1/3 cup vegetable oil
- 1-3/4 cups sugar
- 3 large eggs, room temperature
- 3 large egg whites, room temperature
- 1 tablespoon vanilla extract
- 3 cups cake flour
- 2 teaspoons baking powder
- 1 teaspoon salt
- 1 cup buttermilk, room temperature
- 1/4 cup rainbow sprinkles
For the Chocolate Buttercream and Frosting:
- 8 ounces dark chocolate chips
- 1/4 cup heavy whipping cream
- 2 cups unsalted butter, softened
- 5 cups confectioners’ sugar, sifted
- 1 tablespoon vanilla extract
- 1 pinch salt
Step 1: Make the Cake Batter
You need to start by beating together the room temperature butter, oil and sugar. It should create a light and fluffy mix after about six minutes. Next, add the whole eggs followed by the egg whites one at a time and beat the mixture well after each. The continual beating will ensure that the mixture is full of air, which will make it lighter and fluffier.
The next stage is to add the vanilla. Make sure that you are using good quality vanilla as it will enhance the flavour.
In a separate bowl you should whisk the dry ingredients together, the cake flour, baking powder, and salt. It is important to use cake flour if you want to be sure of a fluffy texture.
Next you should add the dry ingredients to the wet ingredients together with buttermilk. If you don’t have buttermilk, you could use sour cream. Finally, fold in the sprinkles.
Finally, the best part: Fold in the sprinkles.
Step 2: Prepare the Pans and Bake
To start preparing the pans, you should grease three eight-inch round cake pans and line them with parchment or waxed paper. If you are not sure how, then it is easy to find instructions online.
You then need to split the batter equally between the three pans. This is easiest and most accurately done with a kitchen scale. However, you can use measuring cups or just eyeball it.
You then need to place the cakes into a 350F over for 20 to 25 minutes. You can tell they are ready by inserting a toothpick, if it comes out clean then it is time to take the cakes out. You should then let them cool in their pans for 10 minutes before removing them (by inverting them on a wire rack), and then let them cool completely.
Step 3: Prepare the Chocolate Buttercream
A birthday cake isn’t complete without a delicious chocolate buttercream and best of all, it is extremely easy to make.
First, you should combine the chocolate chips and the cream in a microwave-safe bowl. Then microwave it in 30-second increments, stirring gently in between each. You should continue this process until the mixture is melted and it blends together, then let it cool to room temperature.
In a separate bowl, you should beat the room temperature butter until it is light and creamy. Then, slowly add the confectioners’ sugar, the vanilla, salt, and the cooled chocolate mix. Keep beating it for about five minutes, until the frosting is light and fluffy.
Step 4: Frosting
All that is left to do is assemble the cake. You need to start by placing a small amount of the frosting on your cake plate to help hold the base layer in place.
Next, you need to spread the frosting between the layers. It can be hard to get the proportions right, but roughly one cup per layer is what you should aim for. You can measure it out if you want to ensure that the layers look even once the cake has been sliced.
Once you have stacked up the layers of the cake, you should give the outside of the cake a thin layer of icing, known as a crumb coat. It helps to contain the crumbs and gives you a base on which you can spread frosting swirls. Once the crumb coat is on, you can put the cake in the fridge for about 30 minutes or in the freezer for 10.
Next comes frosting. You need an offset spatula and should use it to smooth the frosting on the sides and the top of the cake. Don’t drive yourself mad trying to make it look perfect, it is the imperfections that make the cake look so tempting.
When you have finished frosting the cake, you can add some more sprinkles on top. All that is left to do is add the candles, sing the song, and eat. If you are not going to be eating the cake immediately, you can put it in the fridge until about 30 minutes before it is needed. If you want to make slicing the cake easier, use a knife that has been dipped in hot water and then wiped dry. It will ensure the knife goes cleanly through all the layers and the frosting.
This recipe can be easily adapted. For example, if you don’t want the fuss of a layer cake, then you can simply use the same recipe and bake the cake in a 13x9 pan. It takes a bit longer to bake (about 30 minutes at 325F), but it will save you a bit of time.
You could even turn the recipe into cupcakes. Simply place the batter in lined muffin tins. Don’t overfill them, about three-quarters is enough, and make them for 20 minutes at 350F.