This cake is inspired by the beloved Costco Vanilla Sheet Cake, with white cake layers, vanilla cheesecake filling, and vanilla buttercream. It’s great for any occasion and feeds a crowd!
It’s always good to have a reliable sheet cake recipe in your back pocket for birthdays, anniversaries, or anytime you need to feed a party crowd. But it’s especially good if that sheet cake recipe is filled with vanilla cheesecake mousse. This homemade version of the Costco Vanilla Sheet Cake is made with two 9×13 white cake layers, the aforementioned cheesecake filling, and it’s covered in vanilla buttercream. The decors are up to you and your party theme.
How did I decide to develop this recipe? First of all, I wanted to make a vanilla sheet cake for a special February birthday. And I found a copycat Costco sheet cake recipe online that I was content to use without having to develop my own. However, it was a total disaster. I had an inkling that it would fail after reading through the recipe once. But with hundreds of five star ratings (and curiously, no written reviews) I tried it anyway. After doing some digging on Pinterest, and reading actual text reviews there, I discovered that I wasn’t the only one with terrible results. That’s when I decided to take matters into my own hands.
Why Make your Own Costco Vanilla Sheet Cake?
If you live in close proximity to a Costco, then I understand if you’d prefer to just buy one. Costco Sheet Cakes cost $24.99 for a 12×16-inch cake that feeds 48 people. That’s a deal, if you ask me! However, if – like me – you don’t live near a Costco anymore – this recipe may be a valuable resource. Also, in 2020 when folks weren’t gathering as much, Costco stopped selling their large sheet cakes for a while. But thankfully, they’re back. And hopefully that will never happen again! (However you may want to bookmark this recipe just in case.)
Make the White Cake Layers
First, mix all the dry ingredients in the bowl of an electric mixer: flour, sugar, baking powder, and salt. Then, add room temperature butter to the dry ingredients and mix until the ingredients resemble fine cornmeal. This is called ‘reverse creaming’. It may sound strange, but it’s a tried-and-true method that harks back to the 1950’s. But all you really need to know is that it creates a fluffy cake with a tender crumb. Once the wet ingredients are added, which includes 8 egg whites and 2 whole eggs (add an extra dozen to the shopping list!) the batter becomes thick and smooth. Divide the batter into two 9×13 inch cake pan with sides at least 2 inches deep.
Bake and Cool the Cake Layers
Bake the cakes for about 30 minutes, or until golden on top and set in their centers. Turn them out on wire racks to cool completely. You’ll notice the centers don’t crown or dome too much. This is another benefit of reverse creaming. There is very little leveling to do after the cakes are baked. Some, but not much.
When the cakes are cool, refrigerate them for a couple of hours. This firms the crumb and makes them much easier to level with a serrated knife.
Make the Vanilla Cheesecake Filling
In the bowl of an electric mixer, beat together cream cheese and heavy cream on low speed. You’re not trying to whip the heavy cream, you’re just combining the two ingredients. Next, beat in a little whole milk and a package of instant vanilla pudding. Then, raise the mixer speed to high and beat until thick and fluffy. This combination of ingredients creates a lovely, smooth, not-too-sweet filling that tastes a whole lot like its inspiration!
Top one cake with the entire amount of cheesecake mousse filling, then top with the second white cake layer.
Vanilla Buttercream Frosting
Cover the cake in a classic American buttercream. This formula is just butter, confectioners’ sugar, vanilla extract, and a little milk to thin. The trick to making this kind of buttercream billowy and light, is to beat the heck out of it on high speed. I recommend a stand mixer for this. A sturdy hand mixer could also work but will take a long time.
Pipe a Shell Border
While décor will always vary on the Costco Vanilla Sheet Cake, there’s always one decoration that is a mainstay: a piped border. Use a large open star tip (such as Ateco 826) to pipe a shell border along the bottom and top edges of the cake. If using sprinkles to decorate, sprinkle them on immediately after piping one edge. Because the buttercream crusts easily, if you wait to long they’ll bounce right off.
Add Decors to Match Your Party
This cake is an all-occasions kind of cake. So as I mentioned earlier, the decors are up to you! Red, white, and blue for July Fourth. Red and green for Christmas. Or any mixture of happy sprinkles for a birthday-friendly cake (such as these neon baubles).
I added a pink ‘Happy Birthday’ candle to the center of the cake. Because my finer piping skills are not the best (I’m actively working on improving – but oof! It is hard.) I couldn’t find the exact candle topper I used, but you can find a similar one right here.
Party Cake Cutting Guide
This cake is slightly smaller than the 12×16 Costco cake, at 9×13-inches. However, it’s still a sizeable confection! With two white cake layers, and the filling – it’s hefty. And you can tailor your slices to the size of your party using my guide below. Large Party Size Slices are generous indeed, and would nearly feed 2 people instead of one. The Medium Size Party Slices are more in keeping with what I’d consider a normal serving. However the Small Wedding Size Slices are plenty sufficient for a larger event, and not skimpy-looking on a dessert plate.
This sizeable corner piece shows off the pale fluffy layers and cheesecake filling. The cake slices so beautifully and has a tender, fluffy crumb. Flavor-wise it is smooth and mellow with vanilla, although with more scratch-made flavor than the original Costco White Vanilla Sheet Cake. The filling is quite close to the original – not overly sweet, really smooth and creamy. While the buttercream frosting is the guest that brings the sweetness to the party.
This cake isn’t difficult to make, and most home bakers will have a couple of 9×13 pans in their bakeware arsenal. Use two identical pans if possible, which will prevent extra trimming once assembled. Check out the reverse creaming method in my video if you’re not familiar with the technique. Enjoy!
Related recipe: Bottle of Sprinkles Cake (Homemade Funfetti Sheet Cake)
Costco Vanilla Sheet Cake (Copycat Recipe)
- 9x13x2 inch cake pans, 2
- 12×16-inch cake board, or large platter
- disposable piping bag
White cake layers
- 5 1/4 cups cake flour
- 3 1/3 cups granulated sugar
- 2 tablespoons baking powder
- 1 1/2 teaspoons fine grain salt
- 1 1/2 cups unsalted butter at room temperature
- 8 egg whites from large eggs at room temperature
- 2 whole large eggs at room temperature
- 2 cups whole milk at room temperature
- 1 1/2 tablespoons pure vanilla extract
Vanilla cheesecake mousse filling
- 8 oz. cream cheese softened
- 1/2 cup powdered sugar
- 1 1/2 cups heavy cream
- 1/2 cup whole milk
- 3.4 oz. package instant vanilla pudding mix dry mix
Vanilla buttercream (American)
- 1 lb. unsalted butter at room temperature
- 7 cups confectioners’ sugar
- 2 tablespoons vanilla extract
- Whole milk to thin to spreading consistency
- 1 cup rainbow sprinkles or other decors
White cake layers
- Preheat the oven to 350°F. Grease two identical 9×13-inch baking pans line the bottoms with parchment paper. Lightly grease the parchment paper.
- In the bowl of an electric mixer (stand mixer preferred) combine the cake flour, sugar, baking powder, and salt. Whisk to combine.
- Add the butter to the flour and mix until well incorporated and crumbly, with a texture similar to damp sand or cornmeal. The mixture may also form a paste in humid conditions, this is fine too.
- With the mixer running on low speed, add the egg whites and the whole eggs, one at a time, beating well after each addition. Scrape down the bowl and mix again briefly.
- Add the milk, about 1/3 at a time, to the batter. Beat 1-2 minutes after each addition. Mix in the vanilla extract.
- Divide the batter evenly between the prepared pans. Bake for 26-30 minutes, or until the cakes are golden on top, and a toothpick tester inserted near the center comes out clean. Let cakes cool for 5 minutes in the pan, then turn them out onto wire cooling racks to cool completely. Peel away the parchment paper and discard it.
- Optional step: Wrap and refrigerate cakes for 2 hours, or overnight. This will firm the crumb and make them easier to level.
- When cakes are completely cool, level the rounded tops using a serrated knife.
Vanilla cheesecake mousse filling
- In the bowl of an electric mixer fitted with the whisk attachment, beat the cream cheese until smooth. Add the powdered sugar and mix again until incorporated.
- Add the heavy cream and mix on low until incorporated. Scrape down the bowl and mix again, raising the speed slightly, until the mixture is smooth (you’re not trying to whip the cream, just mix until the two are smooth).
- Add the whole milk; beat to combine Then, add the dry instant vanilla pudding powder. Mix until combined. Scrape down the bowl (sides and bottom) and mix on medium-high speed until the mixture thickens, 2-3 minutes.
- Place a white cake layer on a cake board or serving platter and top with all of the cream cheese mousse. Spread evenly to the edges and top with the second white cake layer. Cover and refrigerate while you make the buttercream.
- In the bowl of an electric mixer fitted with the whip attachment, add the butter and mix until creamy. Add three cups of powdered sugar; mix on low speed until combined, the beat on high speed 1 minute. Add remaining confectioners’ sugar, pulsing the mixer on and off to combine slowly, so the sugar doesn’t fly out of the mixing bowl. Beat until incorporated. Add milk or cream a little at a time to thin. Mix on high speed for 5 minutes, or until lightened in color and billowy. The frosting should lose most of it yellow butter hue.
- Transfer about 1 1/4 cups of the buttercream to a piping bag fitted with a large open star tip; set aside Use the remaining frosting to cover the entire cake, smoothing it evenly with an offset spatula.
- Use the piping bag with the decorator tip to pipe a shell border around the bottom edge of the cake (see video for this action). If using sprinkles, add them after you pipe one edge (wait too long and the sprinkles won’t stick!). Pipe a shell border on the top edge of the cake and add decors, if using.
- Refrigerate cake until the buttercream is set, then cover gently with plastic wrap. Store cake in the refrigerator.
- Bring the cake to room temperature before serving. The cake’s texture, flavor, and filling will be most developed at room temperature.