This perfect yellow sheet cake is the best birthday cake ever. It’s literally perfect. With a fluffy, vanilla-packed yellow cake base and a super silky sour cream chocolate frosting, you will instantly be transported to your childhood. Don’t forget the rainbow sprinkles!
What’s better than a sheet cake? They are the unsung heroes of the baking world. They don’t get nearly the credit they deserve. Sure, a tall confetti layer cake is impressive, but you don’t always want the extra steps of stacking a cake.
But just a simple, amazing yellow cake with a super chocolatey frosting is a forever crowd-pleaser.
Ingredients
So, let’s look at what makes this cake so delicious? There’s a secret in both the cake and frosting – sour cream! It makes the cake extra moist and the frosting extra silky. What else is in this cake? Let’s look through the details.
- All-purpose flour. Usually I use a cake flour, but for a sheet cake I decided to swap in a slightly more sturdy flour.
- Unsalted butter and canola oil. A combination of both is the best balance of flavor and richness.
- Eggs + egg yolks. Eggs are needed for the structure, but the extra yolk brings extra richness. The white can be frozen and saved for things like these mocha meringues.
- Sour cream. I use this is both the cake batter and frosting. A twofer magic ingredient.
- Cocoa powder. I prefer Dutch-processed cocoa (also called “Special Dark” by some companies). Natural cocoa can also be used, but the flavor is richer with Dutch-processed.
- Semi-sweet chocolate. Avoid using chocolate chips which have added stabilizers to prevent them from melting well. Use a baking bar or baking wafer that melts easily.
- Corn syrup. This adds to the shine of the frosting and helps to prevent the chocolate from seizing up.
- Espresso powder. A bit of espresso powder intensifies the chocolate flavor without really adding coffee flavor. It’s like how adding a bit of salt to sweet items makes the flavor better.
Making the Perfect Yellow Sheet Cake
What makes this yellow sheet cake so perfect is that it’s super easy to make. I use the classic creaming method for this cake, following the steps below.
Cream the butter and sugar. Providing the name, creaming the butter and sugar means to whip it on high until it’s super light and fluffy. The lighter and fluffier the butter and sugar, the lighter the final cake texture will be.
Add the eggs slowly. Add the eggs one at a time allowing them to fully blend in before adding the next. This will prevent the batter from splitting.
Alternate dry & wet ingredients. The trick to avoiding overmixing and curdling of the batter is to alternate adding your sifted dry ingredients and the whole milk. Add 1/3 of the flour mixture, slowly let it mix about 75% of the way in. Add 1/2 of the milk, and repeat until just a few streaks remain. Dry – wet – dry – wet- dry.
Hand mix at the end. Even if you are using a hand-mixer, switch to a rubber spatula to mix in the last few streaks of flour and the sour cream. Make sure you scrape down the bottom and sides of the bowl to ensure everything is mixed in evenly.
Super Silky Chocolate Frosting
What good is cake without a banging frosting? Thanks to a mix of unsweetened cocoa powder and semi-sweet chocolate, this not-too-sweet chocolate-forward frosting is the best way to complement the vanilla.
But the secret ingredients are the sour cream making a luscious and silky buttercream and a bit of corn syrup for a touch of shine.
A few tips for making this ridiculously delicious frosting.
Sift ingredients. Both confectioners’ sugar and cocoa powder are notoriously clumpy. Give them a quick sift through a fine-mesh sieve to make sure you have a smooth icing.
Gently melt the chocolate. Chocolate is easy to burn, so melt it gently using a low power on the microwave or using the double boiler method I describe in my tempering chocolate post. Use this time to dissolve the espresso powder.
Add the powdered ingredients slowly. Don’t end up with a powdered sugar bomb in the kitchen. Stir in the cocoa and sugar by hand at first, then very slowly with the mixer until everything is mixed….then increase the speed to whip.
Frequently Asked Questions
Egg whites can be stored and frozen until you need them. I save them up to make things like angel food cake or pavlova.
I would not just leave the chocolate out of this recipe, but feel free to use any frosting you prefer! You can even use that leftover egg white in a Swiss meringue buttercream.
Yes, this cake is great for about 2 days when stored in the fridge. You can also make the cake in advance and freeze it unfrosted for up to 2 months.
I don’t recommend using ceramic for this, it conducts heat too slowly and the cake will not bake the same. Use a metal baking pan for best results.
Yes, you can divide the batter into 2-8″ or 9″ cake pans. Bake for 25-35 minutes depending on cake pan size. Bake until cake springs back when touched and toothpick comes out clean.
Perfect Yellow Sheet Cake with Chocolate Frosting
Equipment
- 9" x 13" metal baking pan
Ingredients
Yellow Cake
- 300 g all-purpose flour
- 2 teaspoons baking powder
- ½ teaspoon baking soda
- 1 teaspoon salt
- 113 g unsalted butter room temperature
- 300 g granulated sugar
- ½ cup canola or vegetable oil
- 3 large eggs room temperature
- 1 large egg yolk room temperature
- 1 tablespoon vanilla bean paste or vanilla extract
- ¾ cup whole milk room temperature
- 113 g sour cream room temperature
Chocolate Frosting
- 56 g semi-sweet chocolate* finely chopped
- 1 teaspoon espresso powder optional
- 227 g confectioners' sugar
- 42 g Dutch-processed cocoa powder
- 170 g unsalted butter room temperature
- 113 g sour cream room temperature
- 2 tablespoons corn syrup
- 2 teaspoons vanilla bean paste or vanilla extract
- 1 teaspoon salt
Instructions
- Yellow cake. Preheat oven to 350°F (175°C). Spray and flour (or use a spray like Baker's Joy) a 13" x 9" metal baking pan.
- In a large bowl, sift together flour, baking powder, baking soda and salt.300 g all-purpose flour, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1 teaspoon salt
- In the bowl of a stand-mixer fitted with paddle attachment, or in a large bowl with a hand-mixer, beat together butter and sugar on high until light and fluffy. About 5 minutes. Scrape down sides of bowl as needed with rubber spatula.113 g unsalted butter, 300 g granulated sugar
- Add oil, mix until smooth and shiny, about 2 minutes. Add eggs, egg yolk and vanilla. Mix on low until fully incorporated, continuing to scrape the sides of bowl as needed.1/2 cup canola or vegetable oil, 3 large eggs, 1 large egg yolk, 1 tablespoon vanilla bean paste or vanilla extract
- On low, add 1/3 of the flour mixture. Once almost incorporated, add 1/2 of the whole milk. Continue alternating until all flour and milk is just mixed with a few streaks of flour remaining.3/4 cup whole milk
- With rubber spatula, stir in sour cream, being sure to scrape the bottom of the bowl to ensure all batter is fully incorporated. Transfer batter to prepared pan, smooth into an even layer and tap on the counter a few times to release any air pockets.113 g sour cream
- Bake for 30-35 minutes, turning cake once during baking if unevenly browning. Cake should be golden brown, spring back when touched, and toothpick comes out clean. Allow to cool completely before frosting.
- Chocolate frosting. While cake bakes, prepare chocolate frosting. In a heat-proof bowl, place chopped semi-sweet chocolate and heat on 50% power in the microwave in 30 second bursts. Stir between. (Alternately can use a double-boiler method). Stir espresso powder, if using, into melted chocolate. Set aside to cool.56 g semi-sweet chocolate*, 1 teaspoon espresso powder
- Over a large bowl, sift together confectioners' sugar and cocoa powder. Set aside.227 g confectioners' sugar, 42 g Dutch-processed cocoa powder
- In a large bowl, whip butter on high until light and fluffy with stand-mixer or hand-mixer. Add in confectioners' sugar mixture, stir by hand a few times to prevent a mess. Mix on low until fully incorporated, then increase speed to whip until smooth.170 g unsalted butter
- Add in sour cream, melted chocolate, corn syrup, vanilla and salt. Continue to whip until smooth.113 g sour cream, 2 tablespoons corn syrup, 2 teaspoons vanilla bean paste or vanilla extract, 1 teaspoon salt
- Spread over cooled yellow cake. Top with sprinkles or candles if desired.
Notes
- *Avoid using chocolate chips – they do not melt well. Use a baking chocolate bar or chocolate wafers that can also be found in the baking aisle.
- Store leftover cake in covered in the fridge for up to 2 days.
- Unfrosted cake can be wrapped in plastic and aluminum foil and frozen for up to 2 months. Defrost in fridge the night before and top with frosting when ready to serve.
Disclaimer: We test all recipes using the metric weights shown, we cannot guarantee outcomes when switching to US measurements.
