Copycat Costco Vanilla Cake Recipe

Introduction

This Copycat Costco Vanilla Cake is a moist, tender cake layered with creamy vanilla buttercream and filled with luscious vanilla mousse. It’s a show-stopping dessert perfect for celebrations or whenever you crave a classic, bakery-style treat at home.

Ingredients

• 2 1/2 plus 2 tablespoons cake flour
• 1 1/2 cups plus 2 tablespoons granulated sugar
• 1 tablespoon baking powder
• 3/4 teaspoon fine salt
• 3/4 cup unsalted butter, very soft
• 4 large egg whites, room temperature
• 1 large egg yolk, room temperature
• 1 tablespoon vanilla extract
• 1 cup buttermilk, room temperature
• 2 tablespoons water
• 2 tablespoons cornstarch
• 1 cup unsalted butter, very soft (for buttercream)
• 1/2 cup vegetable shortening, room temperature
• 4 cups powdered sugar
• 1/2 teaspoon fine salt
• 1 tablespoon vanilla extract (for buttercream)
• 3 to 4 tablespoons whole milk or heavy cream, room temperature
• Copycat Costco Vanilla Mousse (for filling)
• Sprinkles (for decoration)

Instructions

1. Step 1: Preheat your oven to 350°F. Spray two 8-inch cake pans with baking spray and line the bottoms with parchment paper. Set aside.
2. Step 2: In a large bowl, whisk together cake flour, granulated sugar, baking powder, and salt.
3. Step 3: Using a mixer on low speed, gradually add the softened butter into the dry ingredients. The mixture will look sandy or soft depending on your climate. Beat for 1 to 2 minutes, scraping the bowl as needed.
4. Step 4: Add egg whites one at a time, beating well after each addition. Then beat in the egg yolk and vanilla extract.
5. Step 5: With the mixer on low, add the buttermilk in three additions, beating 1 to 2 minutes after each until fully incorporated.
6. Step 6: Divide the batter evenly between the prepared pans. Bake for 26 to 30 minutes, until the cakes are golden and a toothpick inserted comes out mostly clean with a few moist crumbs.
7. Step 7: Let the cakes cool in the pans for 5 minutes before inverting onto a wire rack. Remove parchment and cool completely. If not assembling immediately, wrap and refrigerate.
8. Step 8: To make the buttercream, whisk water and cornstarch together in a small bowl and set aside.
9. Step 9: Beat butter and shortening in a large bowl until light and fluffy, about 3 to 4 minutes, scraping bowl sides as needed.
10. Step 10: Add the cornstarch mixture and mix to combine. Slowly add powdered sugar on low speed, scraping the sides to mix fully.
11. Step 11: Add salt and vanilla extract. If the frosting feels too thick, add milk or cream one tablespoon at a time until smooth and spreadable.
12. Step 12: Level the cake layers with a serrated knife if domed. Place a dab of frosting on a cake board and secure the first cake layer.
13. Step 13: Pipe a ring of frosting around the edge of the first layer, then fill the center with the vanilla mousse filling.
14. Step 14: Top with the second cake layer and coat the entire cake with the remaining buttercream, smoothing with an offset spatula.
15. Step 15: Decorate with sprinkles. Slice and enjoy your delicious homemade copycat Costco vanilla cake!

Tips & Variations

• For extra moist cake, ensure all wet ingredients are at room temperature before mixing.
• Substitute the vegetable shortening in the buttercream with all butter for a richer flavor, but note the texture will be softer.
• Use gelatin to stabilize the mousse filling if assembling the cake a day ahead for firmer layers.
• Add a teaspoon of almond extract to the cake batter for a subtle twist.

Storage

Store the assembled cake covered in the refrigerator for up to 3 days. Bring to room temperature before serving for the best texture and flavor. Leftover cake layers can be wrapped tightly in plastic wrap and frozen for up to 2 months. Thaw overnight in the fridge before frosting and assembling.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I make this cake without buttermilk?

Yes, you can substitute buttermilk with whole milk plus 1 tablespoon of lemon juice or vinegar. Let it sit for 5 minutes before using to mimic buttermilk’s acidity.

How do I prevent the cake from doming while baking?

Make sure to level the batter evenly in the pans and avoid overmixing. Baking strips around the pans or lowering the oven temperature slightly can help the cakes bake more evenly and reduce doming.

Copycat Costco Vanilla Cake Recipe

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5 from 91 reviews

This Copycat Costco Vanilla Cake recipe replicates the beloved bakery-style vanilla layer cake featuring moist, fluffy cake layers and a creamy, smooth buttercream frosting. The cake is filled with a copycat vanilla mousse and adorned with sprinkles for a festive touch. It’s perfect for celebrations and special occasions, offering that perfect balance of classic vanilla sweetness and rich texture.

• Author: Sana
• Prep Time: 25 minutes
• Cook Time: 30 minutes
• Total Time: 55 minutes
• Yield: 12 servings 1x
• Category: Dessert
• Method: Baking
• Cuisine: American

Ingredients

Scale 1x2x3x

For the Cake:

• 2 1/2 cups plus 2 tablespoons cake flour
• 1 1/2 cups plus 2 tablespoons granulated sugar
• 1 tablespoon baking powder
• 3/4 teaspoon fine salt
• 3/4 cup unsalted butter, very soft
• 4 large egg whites, room temperature
• 1 large egg yolk, room temperature
• 1 tablespoon vanilla extract
• 1 cup buttermilk, room temperature

For the Buttercream:

• 2 tablespoons water
• 2 tablespoons cornstarch
• 1 cup unsalted butter, very soft
• 1/2 cup vegetable shortening, room temperature
• 4 cups powdered sugar
• 1/2 teaspoon fine salt
• 1 tablespoon vanilla extract
• 3 to 4 tablespoons whole milk or heavy cream, room temperature

For Assembling the Cake:

• Copycat Costco Vanilla Mousse (prepared separately)
• Sprinkles for garnish

Instructions

1. Prepare the Cake Pans: Preheat your oven to 350°F. Spray two 8-inch cake pans with baking spray and line the bottoms with parchment paper. Set aside to prepare the batter.
2. Combine Dry Ingredients: In a large mixing bowl, sift together the cake flour, granulated sugar, baking powder, and fine salt to evenly distribute all dry ingredients.
3. Mix in Butter: On low speed, gradually add the very soft unsalted butter to the dry mixture. Beat until the mixture resembles coarse sand or looks softer depending on your climate. Continue beating for 1 to 2 minutes, scraping sides and bottom as needed.
4. Add Egg Whites and Egg Yolk: Add the four egg whites one at a time, beating well after each addition to incorporate air for fluffiness. Then beat in the single egg yolk and vanilla extract until combined.
5. Add Buttermilk: With mixer on low, slowly add buttermilk in three additions. Beat for 1 to 2 minutes after each addition to create a smooth, evenly blended batter.
6. Bake the Cakes: Divide the batter evenly between the prepared pans. Bake for 26 to 30 minutes, or until cakes are golden on top and a toothpick inserted into the center comes out with a few moist crumbs but no raw batter.
7. Cool the Cake Layers: Let the pans cool for 5 minutes on a wire rack, then invert to remove cakes and peel off the parchment paper. Allow cakes to cool completely before assembling. Wrap and refrigerate if assembling the next day.
8. Prepare the Buttercream: Whisk water and cornstarch in a small bowl to combine and set aside. In a large bowl, beat the butter and vegetable shortening on medium speed until light and fluffy, about 3 to 4 minutes.
9. Add Cornstarch Mixture and Powdered Sugar: Mix in the cornstarch-water mixture. On low speed, gradually add powdered sugar, scraping bowl sides as needed, until fully incorporated and smooth.
10. Finish Buttercream: Add salt and vanilla extract. If the frosting is too thick, add milk or heavy cream one tablespoon at a time until the desired consistency is reached.
11. Level Cake Layers & Secure Base: If the cakes have domes, use a serrated knife to level them. Place a dab of frosting onto a cake board and secure the first layer.
12. Pipe Frosting Ring & Add Mousse: Fill a pastry bag with some frosting and pipe a ring around the edge of the first layer. Fill the ring’s center with the prepared copycat Costco vanilla mousse.
13. Add Second Cake Layer: Carefully place the second cake layer on top of the mousse-filled base.
14. Frost the Cake: Spread the buttercream evenly over the top and sides of the cake using an offset spatula. Remove excess frosting for a smooth finish.
15. Decorate: Finish by decorating the cake with remaining buttercream and garnish with sprinkles for a festive look. Slice and enjoy your homemade Costco vanilla cake!

Notes

• Ensure all ingredients are at room temperature for best mixing results.
• Softened butter is key to achieving the proper texture for both cake and buttercream.
• Do not overbake cake layers; cake will dry if left too long in the oven.
• For the best mousse filling, prepare it ahead of time so it sets well before assembling.
• Wrap and chill cooled cake layers if assembling the next day to make frosting easier.
• Use an offset spatula for smooth frosting application and a serrated knife for leveling cake domes.
• Adjust milk or cream in buttercream gradually to avoid overly thin frosting.

Keywords: Costco vanilla cake, copycat cake recipe, vanilla layer cake, buttercream frosting, vanilla mousse cake, homemade vanilla cake, birthday cake