Costco Copycat Cake Recipe: Giant-Layered Magic in Your Oven

This Costco copycat cake recipe delivers the same giant-layered magic you love from their bakery, but with a foolproof method you can bake at home. 🌟 I've been testing this for months, and it's the closest I've gotten to that iconic texture and flavor—moist layers separated by rich buttercream that never dries out.

The secret to replicating that Costco signature is a simple trick: baking the cake in a 9x13-inch pan (like their sheet cakes) and using a vanilla bean paste for that signature depth.

I've also included a no-fuss buttercream that stays fluffy even when stacked high—because nobody wants a collapsed cake tower. This recipe serves 12-15, just like the bakery versions you know and love.

What you'll end up with is a towering, golden cake with perfectly moist layers and creamy frosting that stays fresh for days. The vanilla flavor is bright but not overpowering, and the buttercream has just the right amount of sweetness without being cloying.

It's the kind of cake that makes parties feel special without requiring fancy decorating skills.

Want to make it your own? Swap the vanilla for chocolate cake mix, or add a layer of raspberry jam between the tiers for extra flavor. Let's get baking—this one's a game-changer for homemade desserts!

Ingredients for costco cake

Gather these staples to recreate Costco's signature giant-layered cake at home—same magic, better taste.

The vanilla bean paste is non-negotiable for that signature Costco flavor—look for brands like Madagascar vanilla paste at specialty stores or well-stocked supermarkets. King Arthur Flour or Bob's Red Mill are great for the all-purpose flour, but any high-quality brand works. The butter must be full-fat and room temperature—microwave it in 20-second bursts if needed. Eggs should be large, fresh, and room temperature for ideal volume. For the milk, whole milk is best—it adds richness, but 2% works in a pinch. Diamond Crystal baking powder is my go-to for reliable rise, but any brand labeled 'double-acting' will do.

No vanilla bean paste? Double the vanilla extract—it won’t be identical, but it’ll still taste amazing. Short on butter? Coconut oil works in a bind, though the texture won’t be quite the same. The buttercream can be made ahead and refrigerated—just re-whip before using. For the jam filling, seedless raspberry jam is ideal, but strawberry or apricot work too. If you’re short on powdered sugar, sift granulated sugar for a slightly grainier texture. The frosting needs to be stiff but pipeable—chill the bowl for 10 minutes if it’s too soft. No mixer? Use a hand mixer or even a whisk in a pinch, though it’ll take longer.

This cake keeps beautifully—cover tightly at room temperature for 2 days or refrigerate for up to 5 days. The buttercream stays fresh covered in the fridge for 3 days or frozen for 3 months. For make-ahead convenience, bake the cake layers 1 day ahead and store wrapped at room temperature. The frosting can be made 2 days ahead—just re-whip before assembling. Pro tip: Line your 9x13-inch pans with parchment paper for easy removal and a perfect golden crust. Costco’s bakery version uses a sheet cake pan, so mimic that for that iconic texture.

Step-by-step instructions for Costco copycat cake

Here's how to recreate that iconic Costco layered cake at home with perfect texture every time.

Preheat your oven to 350°F and grease three 9-inch round cake pans with baking spray or softened unsalted butter, then line the bottoms with parchment paper. Sift together the 5 cups all-purpose flour, 2.5 cups granulated sugar, 2 tsp baking powder, and 0.5 tsp salt in a large bowl.

In a separate large bowl, cream the 1.5 cups unsalted butter until light and fluffy (about 3-5 minutes with an electric mixer). Add the 6 whole large eggs one at a time, mixing well after each addition. Stir in the 2 tbsp vanilla bean paste and 2 tsp vanilla extract until fully combined. Gradually add the dry ingredients to the wet, mixing on low speed until just combined.

With the mixer on low, slowly pour in the 1.5 cups whole milk until the batter is smooth and pourable. Divide the batter evenly among the prepared pans, spreading it out evenly. Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Let the layers cool in the pans for 10 minutes before transferring to a wire rack to cool completely.

Once the layers are completely cool, level the tops if needed using a serrated knife. Place the first layer on a cake stand or plate. Spread ⅓ of the raspberry jam (if using) evenly over the top, leaving a ½-inch border uncovered. Repeat with the remaining two layers, reserving any leftover jam for the sides if desired.

Here's where the magic happens: for each layer, spread a thin layer of the 1.5 cups heavy whipping cream (whipped to soft peaks) over the jam. This creates a smooth base for the buttercream. I like to use an offset spatula for even distribution—press gently to avoid tearing the cake layers.

In a large mixing bowl, beat the 1 cup unsalted butter (for frosting) and 4 cups powdered sugar together on medium speed until light and fluffy (about 3-5 minutes). Add the 1 tbsp vanilla extract (for frosting) and mix until fully incorporated. Gradually add the 1.5 cups heavy whipping cream (whipped to stiff peaks) and beat until smooth and spreadable.

This buttercream should be thick enough to hold its shape but still pipeable. If it's too thick, add 1 tsp whole milk at a time until you reach the perfect consistency. The key is patience here—don't rush the mixing or the buttercream will be grainy. Taste and adjust sweetness if needed, though the original recipe balances perfectly.

Spread a thin "crumb coat" of buttercream over the entire cake, including the sides. This helps seal in any crumbs and creates a smooth base for the final layer. Chill the cake in the refrigerator for 15 minutes to firm up the buttercream.

Once chilled, apply the final layer of buttercream using an offset spatula, smoothing the sides with gentle pressure. For that signature Costco look, pipe decorative rosettes or swirls around the edges using a piping bag fitted with a star tip. Dust the top lightly with powdered sugar for an elegant finish. Serve at room temperature for the best texture and flavor.

Make-ahead tips for this recipe

Bake Layers Ahead

Bake the cake layers up to 3 days ahead and store them in an airtight container at room temperature. Wrap each layer tightly in plastic wrap to prevent drying. When ready to assemble, simply re-whip the buttercream and stack the layers as directed.

This is my favorite trick for stress-free parties—I bake the layers the night before and assemble in the morning. 📅

Frosting Prep

Make the buttercream 2 days ahead and store it in an airtight container in the refrigerator. When ready to use, let it sit at room temperature for 30-45 minutes before whipping again to restore fluffiness.

I’ve tested this and found the frosting holds up perfectly—just avoid adding extra liquid after refrigeration, as it may alter the consistency. 🥛

Full Assembly Timing

Assemble the cake 12-24 hours before serving to allow the buttercream to set properly. This gives the layers time to meld together and prevents a soggy bottom. I like to assemble mine in the evening and refrigerate overnight—it’s ready to impress the next day without any last-minute stress. 🎂

Storage Hacks

Keep the fully frosted cake at room temperature for up to 2 days in a cool, dry place. For longer storage, refrigerate for up to 5 days, but let it sit at room temperature for 30 minutes before serving to soften the buttercream slightly.

I’ve even frozen fully assembled cakes (without powdered sugar dusting) for up to 3 months—just thaw in the fridge overnight. ❄️

Jam Filling Flexibility

Prepare the jam filling 1 day ahead and store it in a small airtight container in the refrigerator. Warm it slightly before spreading to make it easier to work with. I’ve used this trick with homemade jam too—just ensure it’s fully cooled before assembling to avoid melting the buttercream. 🍓

Equipment Shortcuts

No cake stand? Use a large, sturdy plate or even a wooden cutting board lined with parchment paper. For piping decorations, a ziplock bag with a corner snipped off works in a pinch if you don’t have piping tips.

I once used a spoon to spread buttercream in a hurry—it’s not perfect, but it gets the job done for a casual gathering. 🧑‍🍳

Frequently asked questions