Classic Vanilla Birthday Cake With Chocolate Buttercream

Why You’ll Love This Recipe

• Tender, bakery-style vanilla crumb thanks to buttermilk and proper creaming.
• Deep, chocolatey buttercream with a silky, whipped finish and just-right sweetness.
• Classic flavor pairing that everyone loves, dressed up with cheerful rainbow sprinkles.
• Step-by-step guidance for even layers, clean slices, and party-perfect results.

Grocery List

• Produce: None
• Dairy: Unsalted butter, eggs, buttermilk, heavy cream
• Pantry: Cake flour, granulated sugar, powdered sugar, unsweetened cocoa powder, baking powder, baking soda, fine sea salt, pure vanilla extract, neutral oil, espresso powder (optional), rainbow sprinkles, parchment paper

Full Ingredients

For the Vanilla Cake

• 3 cups (360 g) cake flour
• 2 1/2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1 teaspoon fine sea salt
• 1 cup (226 g) unsalted butter, softened to room temperature
• 1 3/4 cups (350 g) granulated sugar
• 4 large eggs, at room temperature
• 1 tablespoon pure vanilla extract
• 1 1/4 cups (300 ml) buttermilk, at room temperature
• 1/3 cup (80 ml) neutral oil (canola or vegetable)

For the Chocolate Buttercream

• 1 1/2 cups (340 g) unsalted butter, softened
• 1 cup (100 g) unsweetened cocoa powder (Dutch-process recommended, natural works)
• 5 cups (600 g) powdered sugar, sifted
• 1/2 cup (120 ml) heavy cream, plus 1–3 tablespoons more as needed
• 2 teaspoons pure vanilla extract
• 1/2 teaspoon fine sea salt
• 1 teaspoon instant espresso powder (optional, enhances chocolate flavor)

To Finish

• 1/2 cup (80 g) rainbow sprinkles, plus extra if desired
• Nonstick spray or butter and flour for pans, and three parchment rounds

Step-by-Step Instructions

Step 1: Prep pans and oven

Position racks in the center of the oven and heat to 350°F (177°C). Grease three 8-inch round cake pans with nonstick spray or butter, line the bottoms with parchment rounds, then lightly flour the sides. This helps the layers release cleanly and rise evenly.

Step 2: Mix dry ingredients

In a medium bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set aside. Having your dry mix ready makes for a smoother batter and prevents overmixing later.

Step 3: Cream butter and sugar, then add eggs and vanilla

In a large bowl with a hand mixer or in a stand mixer fitted with the paddle, cream the softened butter and granulated sugar on medium speed until very light and fluffy, 3–4 minutes. Beat in the eggs one at a time, scraping the bowl after each addition. Mix in the vanilla. Proper creaming builds structure and a fine crumb.

Step 4: Combine wet and dry without overmixing

Stir the oil into the buttermilk. With the mixer on low, add the dry ingredients in three additions, alternating with the buttermilk-oil mixture, beginning and ending with dry (dry, wet, dry, wet, dry). Mix just until the last streaks of flour vanish. The batter should be smooth and thick; avoid overmixing.

Step 5: Divide and bake

Divide the batter evenly among the prepared pans (about 2 1/2 to 3 cups per pan; use a scale for precision). Smooth the tops. Bake 23–27 minutes, rotating pans once halfway through, until the centers spring back and a toothpick comes out with a few moist crumbs. Do not overbake.

Step 6: Cool completely and level

Cool cakes in pans on a rack for 10 minutes. Run a thin knife around edges, invert onto racks, peel off parchment, and cool completely, 60–90 minutes. If domed, level the tops with a serrated knife for stable stacking and neat layers.

Step 7: Make the chocolate buttercream

Sift the cocoa powder and powdered sugar together to remove lumps. In a large bowl, beat the butter on medium-high until very creamy and pale, 2–3 minutes. Beat in half of the sugar-cocoa mixture, followed by the cream, vanilla, salt, and espresso powder (if using). Add the remaining sugar-cocoa and beat 2–3 minutes until fluffy. Adjust with a tablespoon or two more cream for a smooth, spreadable consistency.

Step 8: Fill, crumb coat, chill, and finish

Place one cake layer on a turntable or serving plate. Spread about 3/4 cup buttercream over the top, edge to edge. Repeat with the second layer. Top with the final layer, cut side down. Apply a thin crumb coat over the entire cake and chill 20 minutes to set. Finish with a generous final coat, creating swirls with an offset spatula. Press rainbow sprinkles along the bottom edge and scatter more on top. Slice with a warm knife for clean pieces.

Pro Tips

• Room temperature ingredients mix more evenly and produce a finer crumb.
• Weigh batter into pans for perfectly even layers and consistent baking.
• Use cake strips or wrap pans with damp strips to minimize doming.
• Stop mixing as soon as dry streaks disappear to avoid a tough cake.
• For deeper chocolate flavor, use Dutch-process cocoa and a pinch of espresso powder.

Variations

• 9×13-inch sheet cake: Bake at 350°F (177°C) for 35–40 minutes. Frost the top generously and add sprinkles.
• Two 9-inch rounds: Bake 28–32 minutes. You may have a little extra buttercream.
• Cupcakes: Yields about 24. Bake 18–22 minutes; pipe swirls of buttercream and sprinkle.

Storage & Make-Ahead

Store the frosted cake covered at cool room temperature for up to 1 day or refrigerate up to 4 days (bring to room temperature before serving). Unfrosted cake layers can be wrapped well and refrigerated for 2 days or frozen up to 2 months; thaw in wrap. Buttercream keeps refrigerated up to 1 week or frozen up to 2 months; bring to room temperature and rewhip with a splash of cream before using.

Nutrition (per serving)

Approximate for 1 of 16 slices: 690–720 calories; 40 g fat; 86 g carbohydrates; 6 g protein; 2 g fiber; 360 mg sodium; 61 g sugars. Values will vary with brands and decoration amounts.