Description
This 9×13-inch yellow birthday cake is soft, buttery, and topped with rich chocolate fudge frosting. Made from basic ingredients and easy to decorate, it’s the perfect homemade cake for birthdays, parties, and celebrations.
Ingredients
- 2 and 1/4 cups (266g) cake flour (spooned & leveled)
- 2 teaspoons baking powder
- 1/4 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup (16 Tbsp; 226g) unsalted butter, softened to room temperature
- 1 and 1/2 cups (300g) granulated sugar
- 2 large eggs, at room temperature
- 2 teaspoons pure vanilla extract
- 2/3 cup (160g) sour cream, at room temperature*
- 1 cup (240g/ml) whole milk, at room temperature*
Chocolate Fudge Frosting
- 1 cup (16 Tbsp; 226g) unsalted butter, softened to room temperature
- 4 and 1/2 cups (540g) confectioners’ sugar
- 3/4 cup (62g) natural unsweetened or dutch-process cocoa powder
- 1/2 cup (120g/ml) whole milk
- 1 Tablespoon light corn syrup*
- 1 and 1/2 teaspoons pure vanilla extract
- 1/8 teaspoon salt
- optional: rainbow sprinkles
Instructions
- Preheat the oven to 350°F (177°C). Generously grease a 9×13-inch baking pan. Set aside.
- In a large bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set aside.
- In a large bowl using a handheld or stand mixer fitted with a paddle attachment, beat the butter and sugar together on medium-high speed for 3 full minutes. Scrape down the sides and bottom of the bowl with a silicone spatula as needed. Beat in the eggs and vanilla extract until combined. Scrape down the sides and bottom of the bowl as needed. Beat in the sour cream.
- Add half of the dry ingredients and half of the milk and beat on low speed until combined. Add the remaining dry ingredients and milk and beat on low speed until combined. Do not over-mix this batter. The batter will be smooth, velvety, and slightly thick. You may need to whisk it all by hand to make sure there are no lumps at the bottom of the bowl.
- Spread the batter into the prepared pan and smooth it into an even layer. Bake for 32–38 minutes or until the top is very lightly browned and a toothpick inserted in the center comes out clean. Rotate the pan halfway through baking and, if you notice the top and edges quickly browning, tent the cake with aluminum foil.
- Remove from the oven and allow the cake to cool in the pan placed on a wire rack. As the cake finishes cooling, make the frosting.
- Make the frosting: Using a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium-high speed until pale, smooth, and creamy, about 3 minutes. Using a fine mesh strainer, sift the confectioners’ sugar and cocoa together. Add the sugar/cocoa mixture to the butter, then beat on low speed until the sugar is mostly incorporated, about 20 seconds. Stop the mixer, then add the milk, corn syrup, vanilla, and salt. Beat on medium-high speed for 2 minutes. If the frosting is too thick, beat in an extra splash of milk.
- Spread the frosting over the cooled cake and top with sprinkles, if desired. Slice and serve.
- Cover leftovers tightly and store in the refrigerator for up to 5 days.
Notes
- Make Ahead & Freezing Instructions: Cake can be made 1 day in advance, covered tightly at room temperature, and then frosted right before serving. Frosting can also be made 1 day ahead of time. Cover tightly and refrigerate overnight. Bring frosting to room temperature, then beat the frosting on medium speed for a few seconds so it’s creamy again. Adding a splash of milk will help thin the frosting out, if needed. Frosted or unfrosted cake can be frozen up to 3 months. Thaw overnight in the refrigerator before serving.
- Special Tools (affiliate links): 9×13-inch Metal Baking Pan or this 9×13-inch Metal Baking Pan | Glass Mixing Bowl | Whisk | Electric Mixer (Handheld or Stand) | Silicone Spatula | Cooling Rack | Fine Mesh Strainer | Icing Spatula
- Cake Flour: Cake flour produces an extra light cake, and I strongly recommend it here. In a pinch, you can try this cake flour substitute.
- Sour Cream: Full-fat sour cream lends the best flavor. You can substitute plain yogurt in a pinch. I suggest a full-fat variety.
- Milk: For a rich and moist cake, I highly recommend whole milk. You can use lower-fat or nondairy milk in a pinch, but the cake won’t taste as rich or moist. You can use buttermilk instead, too. I recommend whole milk or even half-and-half in the frosting, but lower-fat or nondairy milk works in a pinch.
- Corn Syrup: A little corn syrup makes the frosting uniquely glossy and shiny. You can leave it out if you’d like.
- Yellow Cupcakes: You can use this cake batter to make about 20 cupcakes. I also have a yellow cupcakes recipe that produces the same buttery, moist texture and flavor. If using this cake batter, follow the same baking instructions as the yellow cupcakes.
- Yellow Layer Cake: Here is my yellow layer cake recipe.
- Update in 2026: We updated this recipe with 2 small changes for more effective leavening and to produce a moister crumb. To make it as written originally, increase baking powder to 2 and 1/2 teaspoons and decrease sour cream to 1/2 cup (120g).