If there’s only one cake you ever learn to make, let it be this. Yellow cake swaddled in chocolate frosting is perhaps the gold standard cake for birthdays, and for good reason–it strikes just the right balance of chocolate and vanilla. Here, we go the extra mile with a shockingly simple frosting that tastes like deluxe chocolate custard, an über-tender crumb thanks to reverse creaming and cake flour, and colorful “confetti” sprinkles inside and out. We’re celebrating, aren’t we?
When it comes to those sprinkles, choose wisely. Tiny multicolored nonpareils immediately dissolve into a streaky mess of color. Instead, look for ice-cream-parlor-style rainbow sprinkles or flat, round confetti quins (available online and at baking or craft supply stores) for distinct dashes of color.
For the silkiest frosting, bring the sour cream (and the eggs and butter while you’re at it) to room temperature. Fridge-cold sour cream will harden the melted chocolate on contact and the resulting tiny shards will be impossible to fish out. Even if you think you’re too grown-up for milk chocolate, use it anyway for a well-balanced frosting.
All products featured on Bon Appétit are independently selected by our editors. However, when you buy something through the retail links below, we earn an affiliate commission.
What you’ll need
Rainbow Sprinkles
$15 At Amazon
Stand Mixer
$330 $250 At Amazon
8-Inch Cake Pan
$10 At Amazon
Decorating Turntable
$10 At Walmart
Scale
$26 At Amazon
Round Parchment Paper Baking Sheets
$11 $9 At Amazon
Rubber Spatula
$13 At Amazon
Recipe information
Yield
12 servings
Ingredients
Cake
¾
3
½
2¼
1½
2
2
¼
½
1
¼
½
Frosting and assembly
12
12
2½
1½
1
Preparation
Cake
Step 1
Place a rack in middle of oven; preheat to 350°. Lightly grease sides of two 8"-diameter cake pans with unsalted butter (do not grease bottoms). Line pans with parchment paper rounds. Whisk 3 large eggs, room temperature, and ½ cup plus 2 Tbsp. whole milk in a small bowl to blend; set aside.
Step 2
Mix 2¼ cups (281 g) bleached cake flour, 1½ cups (300 g) granulated sugar, 2 tsp. baking powder, 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt, and ¼ tsp. baking soda in the bowl of stand mixer fitted with the paddle attachment on low speed until well combined, about 1 minute. Add ¾ cup (1½ sticks) unsalted butter, room temperature, cut into 1" pieces, increase speed to medium-low, and beat until mixture resembles breadcrumbs, about 1 minute. Add ½ cup (115 g) sour cream, 1 Tbsp. vanilla bean paste or vanilla extract, and ¼ tsp. almond extract; beat until batter is pale and fluffy, about 1 minute.
Step 3
Add reserved egg mixture to batter in 4 or 5 additions, beating to blend between additions and scraping down sides of bowl with a rubber spatula as needed; batter should be smooth and creamy. Fold in ½ cup rainbow sprinkles or confetti quins until evenly dispersed. Scrape batter into prepared pans, dividing equally (about 590 g per pan); smooth surface with an offset spatula.
Step 4
Bake cakes until golden and tops spring back when lightly pressed (an instant-read thermometer inserted into the center should register 205°), 25–30 minutes. (Cakes may start to shrink slightly from edges of pan.) Transfer pans to a wire rack and let cakes cool 10–15 minutes. Run an offset spatula around sides of cakes to loosen, then invert onto rack; peel away parchment. Let cakes cool completely, at least 1 hour.
Do ahead: Cakes can be baked 1 day ahead. Store tightly wrapped at room temperature.
Frosting and assembly
Step 5
Heat 12 oz. milk chocolate, chopped, and 12 oz. semisweet chocolate, chopped (about 50% cacao), in a large heatproof bowl set over a saucepan of barely simmering water (do not let bowl touch water), stirring with a rubber spatula, until just melted and smooth, about 5 minutes. Remove bowl from heat. Vigorously whisk in 2½ cups sour cream, room temperature, 1½ tsp. Diamond Crystal or 1 tsp. Morton kosher salt, and 1 tsp. vanilla bean paste or vanilla extract until mixture is smooth and resembles pudding (it may look stiff at first, but keep stirring). Use immediately. (If frosting feels very loose—might happen if the chocolate was very hot—let sit at room temperature 20–30 minutes to firm up slightly before assembling cake.)
Step 6
Place 1 cake layer, right side up, on a cake stand or large plate (use a cake turntable if you’ve got one; it makes frosting easier). Scoop a heaping cupful of frosting on top and spread evenly with offset spatula. Place second cake layer, upside down, on top. Spread top and sides of cake evenly with remaining frosting. Using a spoon or offset spatula, create decorative swirls and divots in frosting if desired. Top with rainbow sprinkles or confetti quins (the limit does not exist). Let cake sit at room temperature at least 30 minutes to allow frosting to firm up slightly before serving.
Do ahead: Cake can be assembled 12 hours ahead. Cover with a cake dome or an inverted bowl and store at cool room temperature.