You guys! My baby turned TWO a few weeks ago and I can’t quite believe it. Like, where did my sweet, squishy babe go and where did this jumping, climbing, shouting (always with the shouting), little weirdo come from? I mean, yes, the sweet babe is still there, giving me sloppy kisses and asking ever-so-sweetly, “Otay, Mama?” every time I sneeze (srsly, I die). But man, all those cliches about growing up too fast are so true.
Our celebration was small but exactly how we like to do things–Casper’s aunt and uncle came over and we walked to this great pizza place in our neighborhood (FWIW, Pizzeria Otto in NE Portland), then walked home for cake. I figure we can keep the birthday fêtes simple until he’s older and has friends and actually cares about a party. Even though we went low-key, you know I had to make a fun cake! I love an opportunity to make a layer cake and while Sean always wants chocolate-covered-chocolate with extra chocolate, I can do whatever I want for Casper (until he tells me otherwise, which I’m guessing will be on the horizon sooner than I’d like). Thus, this rainbow marbled wonder was born and it just gives me all the same feelings I’d get flipping through my Lisa Frank sticker book circa 1993. While the rainbow marble effect is super fun and totally aesthetic, the actual cake is a solid vanilla bean and buttermilk batter that bakes up flat-topped layers with a fine, tender crumb. You could frost this with any frosting you want–it’s a basic vanilla cake so the pairings are really endless–but, I went with vanilla bean Swiss meringue buttercream. It’s from Tessa’s book, Layered, and makes just enough to fill and frost an 8-inch layer cake. In my opinion, it’s a dream to work with and always produces the silkiest frosting that isn’t too sweet, holds up well, and tastes great, too.
- 3 ¾ cups AP flour
- 1 teaspoon baking powder
- ½ teaspoon soda
- ¾ teaspoon Kosher salt
- 3 sticks unsalted butter, softened
- 2 ¼ cups sugar
- 2 vanilla beans (or 1 tablespoon extract)
- 1 cup buttermilk
- 3 eggs plus 1 yolk
- Gel food coloring plus 1 tablespoons of buttermilk or milk for each color
- Preheat the oven to 350°F. Line and spray 3, 8-inch, cake pans.
- Whisk flour, baking powder, baking soda, and salt in a mixing bowl. Set aside.
- In the bowl of a mixer, beat the butter until smooth and creamy. Beat in the sugar and the insides of the vanilla beans (or extract), mix for 2-3 minutes until pale and fluffy. Beat in the eggs, one at a time, mixing well after each addition and scraping the bowl as needed. Next, beat in ⅓ of the flour mixture, followed by half of the buttermilk, and repeat ending with the flour mixture until just incorporated. Separate the batter into bowls (the number depending on how many colors you are using). Mix each gel color with 1 tablespoon of buttermilk or milk, fold one color into each bowl of batter. Divide the batters between each cake pan, making sure there are scoops of each color of batter in each pan, using a skewer or butter knife, swirl the batter a few times in each pan. Smooth the tops as best as you can and tap each pan on the counter a few times to even out the surface of the batter and release any large bubbles. Bake for 25 minutes or until the cakes spring back to the touch and a toothpick inserted in the center comes out clean. Cool completely on a wire rack before frosting.
- To frost the cake:
- Spread a tablespoon of frosting onto a cake board or cake plate and place the bottom cake layer on top--this will keep the cake in place and prevent sliding. Spread about ½ cup of frosting over the first layer, stacking the second layer on top and repeat. Once the cake is filled and stacked, spread a thin layer of frosting over the entire cake--this is the crumb coat, it's a thin layer of frosting that catches the loose crumbs and prevents them from getting into the final coating of frosting. Smooth out the crumb coat as much as possible and refrigerate until firm--at least 1 hour. Use the remaining frosting to give the cake a final decorative layer of icing.
I used whole vanilla beans in this recipe, though you can use extract or paste (about 1 tablespoon in the cake and 2 teaspoons for the frosting). When I buy vanilla beans, I store them upright in a lidded jar with about ½ inch of clear, flavorless alcohol (like vodka). This keeps the beans from drying out and when it comes time to use one, instead of splitting & scraping, I just snip off one end squeeze all the way down from the other end and into my recipe. Then I pop the pod into a jar of sugar or alcohol (for extract).
I used 8-inch round cake pans with 3-inch sides for this recipe.
This amount of batter also makes a 3-layer, 6-inch, cake plus 12 cupcakes.
For the sprinkles, I used Sweetapolita Carousel Sprinkle Medley and clear sanding sugar.
- 4 egg whites
- 1 cup granulated sugar
- 2 cups (4 sticks) unsalted butter, at room temperature
- 1 vanilla bean (or 2 teaspoons extract)
- Place the egg whites and sugar into the bowl of a stand mixer and whisk lightly to moisten the sugar. Fill a saucepan with a few inches of water and bring to a simmer over medium heat. Place the bowl over the pan of water to create a double boiler (the water should not touch the bottom of the bowl) and stir occasionally until the mixture is hot and the sugar has dissolved. To test this, dip a finger into the mixture--it should be hot to the touch and when rubbed between two fingers should not contain any sugar granules. If there are still some bits of sugar, keep heating and stirring. Once the mixture is ready, place the bowl on the stand mixer and fit with the whisk attachment. Beat on high for about 10 minutes until a medium stiff meringue forms and the bowl has returned to room temperature and heat no longer escapes from the meringue. Switch the whisk attachment for the paddle attachment and, with the mixer on low, add the butter a few tablespoons at a time, followed by the vanilla bean seeds. Once everything has been incorporated, turn the mixer to high and beat for 3 to 5 minutes until the buttercream is silky and smooth. Use the frosting immediately or store in a lidded container in the refrigerator until ready to use. If you refrigerate the buttercream, bring it back to room temperature on the counter and then beat with a mixer until smooth.
The butter should be soft but not so soft it can't hold its shape, is melty, or appears greasy on the surface.
If the buttercream looks curdled, just keep mixing it! There are many troubleshooting references online and in books for swiss meringue buttercream, but I often find that mixing it longer will do the trick most of the time.