Name: Copycat Costco Vanilla Cake Recipe
Prep time: 25 min
Cook time: 30 min
Total time: 55 min
Cuisine: American
Ingredients: 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; 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; Copycat Costco Vanilla Mousse (prepared separately); Sprinkles for garnish

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Introduction

This Copycat Costco Vanilla Cake is a delightful treat that captures the same fluffy texture and rich flavor of the beloved store-bought version. With moist layers and a smooth buttercream frosting, this recipe is perfect for celebrations or a special dessert at home.

Two slices of two-layer vanilla cake with white frosting sit on white plates with delicate floral patterns. The cake layers are light golden with smooth white cream filling between them. The top edges have small piped decorations in blue and light purple, adding a soft, colorful touch. Each plate has a silver fork placed beside the cake slice. Part of the whole cake with similar decoration is visible in the top right corner on a white cake stand. The setting is on a soft, light cloth over a white marbled surface with a few pastel candles and tiny colorful sprinkles scattered around. Photo taken with an iphone --ar 4:5 --v 7

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 (for buttercream)
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

Step 1: Preheat your oven to 350°F. Spray two 8-inch cake pans with baking spray, line the bottoms with parchment paper, and set aside.
Step 2: In a large bowl, combine cake flour, granulated sugar, baking powder, and salt. With a mixer on low speed, gradually add the softened butter. The mixture will look sandy or soft depending on your climate, both are fine.
Step 3: Beat the batter for 1 to 2 minutes, scraping down the sides and bottom of the bowl.
Step 4: Gradually add egg whites one at a time, beating well after each addition. Mix in the egg yolk and vanilla extract.
Step 5: On low speed, gradually add buttermilk in three additions, beating for 1 to 2 minutes after each addition.
Step 6: Divide the batter evenly between the prepared pans and bake until the tops are golden and a toothpick inserted comes out with a few moist crumbs, about 26 to 30 minutes.
Step 7: Let the cake layers cool in the pans for 5 minutes, then invert onto a wire rack and cool completely. Remove the parchment paper. If not assembling immediately, wrap in plastic wrap and refrigerate.
Step 8: For the buttercream, whisk together water and cornstarch in a small bowl and set aside.
Step 9: Beat butter and shortening in a large bowl until light and fluffy, about 3 to 4 minutes. Scrape the bowl as needed.
Step 10: Add the cornstarch mixture and mix to combine. On low speed, gradually add powdered sugar, scraping the bowl as needed.
Step 11: Mix in salt and vanilla extract. If the frosting is too thick, add milk one tablespoon at a time until the desired consistency is reached.
Step 12: To assemble, level cake layers with a serrated knife if domed. Secure the first layer on a cake board with a bit of frosting.
Step 13: Pipe a ring of frosting around the edge of the first cake layer using a pastry bag. Fill the center ring with the vanilla mousse.
Step 14: Place the second cake layer on top, coat the entire cake with buttercream, smoothing with an offset spatula.
Step 15: Decorate with remaining frosting and sprinkles. Slice and enjoy your homemade Copycat Costco Vanilla Cake!

Tips & Variations

Use room temperature ingredients to ensure a smooth batter and even baking.
For a lighter texture, carefully fold in whipped egg whites instead of beating them directly into the batter.
Substitute buttermilk with regular milk plus 1 tablespoon of lemon juice or vinegar if needed.
Add lemon zest to the buttercream for a fresh twist on flavor.
For a fun decoration, use colorful sprinkles or fresh berries instead of canned sprinkles.

Storage

Store the assembled cake covered in the refrigerator for up to 3 days. To keep the cake fresh, place it in an airtight container or cover with plastic wrap. When ready to serve, remove from the fridge about 30 minutes beforehand to soften the buttercream. Leftover cake layers can be wrapped tightly and frozen for up to 2 months.

How to Serve

A slice of two-layer yellow cake is shown with smooth white frosting covering the sides and a thick layer of frosting between the two cake layers. The cake texture looks soft and moist with a golden brown edge on the top of each layer. There is a swirl of light blue frosting with small colorful sprinkles on the top right side of the slice. The dessert is placed on a white plate with pink floral patterns, and a silver fork rests beside the cake. The background is a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use all-purpose flour instead of cake flour?

While all-purpose flour can be used, cake flour produces a lighter, more tender crumb. If using all-purpose flour, remove 2 tablespoons per cup and replace with cornstarch for a better texture.

How do I make the Copycat Costco Vanilla Mousse filling?

The mousse is typically a light, creamy filling made from whipped cream and vanilla flavoring. Many recipes combine whipped heavy cream with vanilla pudding or custard to achieve a similar texture. For best results, use a trusted mousse recipe or a pre-made vanilla mousse.